First, by "celibacy" the Economist article seems to be talking about less sex.
And this part is basically correct if we restrict it to younger people (again the narrower actual topic of the Economist article).
From the BBC, which identifies its sources (unlike the Economist on this topic):
Survey results from the National Opinion Research Center (NORC) at the University of Chicago, which have been interpreted and analysed by the the Washington Post, suggest that fewer young men in the US are having sex than in the past.
The General Social Survey, which interviews thousands of people and has been conducted since 1972, revealed that 23% of adults said they hadn’t had sex in the past year - doubling in the past 10 years - and that “a much larger than expected” number of them were men.
The survey shows that the share of men under 30 who said they hadn’t had sex in the past year has tripled since 2008 to 28% - much higher than the 8% increase among women in the same age range.
The last paragraph is reporting exactly the same data as the Economist article (in a section thereof you haven't quoted.)
But the BBC also gives some related figures not mentioned by the Economist:
The data, obtained from face-to-face interviews, also found that more than half of US adults between the ages of 18 and 34 (51%) don’t have a long-term partner - a figure that’s risen from 33% in 2004.
As for the reasons behind these trends, everyone has a theory: Netflix, videogames, social media, the nature of dating apps, the increase in cohabitation with parents, and various anxieties are just some potential reasons mentioned by the BBC. Alas there don't seem to much studies on the causes of these trends, and as with epidemiological research, it would be hard to prove causation anyway.
Aside, there's a very recent BMJ article that found a somewhat similar trend in the UK, except the decline was "more markedly among those in early middle age"; it also says that research is needed to identify the causes. But it has this insightful observation (regarding UK data):
the decline is not consistent across the socioeconomic spectrum; it is seen among better-off and worse-off men, but not among men of average material status. Among men in higher status jobs, who generally report higher frequency of sex, the decline may reflect the increasing pace of modern life; among men who are worse off, the decline could be attributable to stresses caused by financial hardship and less job security.
It's not clear to me if the equivalent US research has even attempted that breakdown.
Also there's a 2018 article in The Atlantic that provides an even wider cross-cultural perspective: it additionally covers Japan and some European countries. Lots of potential reasons are covered in this article as well: later marriages, mastubration/porn, increased inhibitions of various kinds e.g. flirtations no longer being acceptable in the workplace, dating apps favoring the few (good looking ones), porn-inspired behavior of men turning women off, decreased adolescent dating because of their overloaded schedules and/or "helicopter parents" etc. You can probably ask one or two dozen Skeptics questions based on all the hypotheses advanced on this issue of what causes less nowadays; but most will probably not get any good answers causality-wise.
But some (and probably most) of these are known to be insuficient explanations or outright irrelevant, e.g.:
While it is true that younger couples are waiting longer to have sex and getting married later, that’s not enough to explain the decline, especially since the drop was largest among couples who were married or living with partners.
Various socially conservative theories, such as attributing the decline in sex to the increase of women in the workforce, or to couples in general working longer hours, have been debunked. In fact, the reverse is true, with the busiest couples reporting the highest sexual frequency. And while pornography can sometimes pose issues for modern relationships by leading to unrealistic expectations, hindering intimacy, and, in extreme cases, leading to infidelity, researchers haven’t found its use to be correlated with a decline in sexual frequency.
There are other possible explanations, such as economic insecurity, or the increased social acceptance for women to have more sexual agency. But the point is: None of these reasons is enough, on its own, to explain the findings. [...]
Conventional gender roles, which only sexually empower men, may lead to more sex, but not necessarily to more satisfaction. In other words, egalitarian couples have greater sexual satisfaction than those with conventional gender roles.
(Alas this academic source doesn't provide much data or citations to back up its claims.)
Of course, as the Economist formulated it "economics [or] technology" covers almost any conceivable reason outside of some biological or environmental change, and since those have not been suggested (among the plethora of hypotheses), you could probably rate the Economist's claim as uniformatively true with respect to those two items.
The "female empowerment" angle is probably the least vague of the Economist claims and it is reflected in other sources; there's even some data backing it up (in the more concrete formulation from the last/academic quote):
Using data from Wave II of the National Survey of Families and Households, this study investigates the links between men’s participation in core (traditionally female) and non-core (traditionally male) household tasks and sexual frequency. Results show that both husbands and wives in couples with more traditional housework arrangements report higher sexual frequency, suggesting the importance of gender display rather than marital exchange for sex between heterosexual married partners.
However another study attempting to confirm this on a newer data set, failed:
Although contemporary couples increasingly express preferences for egalitarian unions, previous research has suggested that sexual intimacy decreases when routine housework is shared. Yet this research was conducted on data that are decades old. To update this work, the authors compared data from the 2006 Marital and Relationship Survey (MARS) and Wave 2 of the National Survey of Families and Households (NSFH2), collected in 1992–1994. The results indicated change in the association between housework arrangements and sexual intimacy across surveys. Although egalitarian arrangements were associated with lower sexual frequency compared to conventional arrangements in the NSFH2, no such difference was found in the MARS. In fact, reported sexual frequency increased across surveys among egalitarian couples only.
To pick almost randomly some of the economics-related studies... Here are some from a review:
While men tended to receive more education than women in the past, the gender gap in education has reversed in recent decades in most Western and many non-Western countries. [...]
Speed dating experiments and online dating studies conducted in the US support the idea that men avoid female partners with characteristics associated with economic success such as high educational attainment and ambition, at least in the early 2000s, when the data were collected (Fisman et al. 2006; Hitsch et al. 2010). It is not clear whether this also holds for long-term relationships. Preferences may differ for short-term versus long-term relationships (Stewart-Williams and Thomas 2013).
So in these you have the interaction of female empowerment in the sense of economic/educational empowerment and technology changes (online dating) producing a result potentially diminishing sexual encounters and thus activity. It's not too clear if the supply-demand equation of sex can or cannot eventually balance these changes (e.g. by men culturally adapting to these changes.)
Economic empowerment may also impact the stability of long-term relationships (again potentially leading to less sex):
Complaints and feelings of unfairness about the division of unpaid work may undermine union satisfaction, which may ultimately lead to union dissolution. In a qualitative study of 120 men and women living in the New York metropolitan area, Gerson (2011) found that a majority of young adult women and men alike aspired to have an egalitarian relationship, sharing paid work in the labor market and unpaid work at home. At the same time, despite their shared aspirations, men and women seem to be skeptical about that the egalitarian ideal would be realized. When asked about their fallback strategies, women and men appeared to hold strongly divergent ideals. While the majority of men wanted to revert to traditional gender roles as a fallback plan, most women said they would opt for going it alone if they were faced with that option.
If you also consider that some research indicates that women have better sexual satisfaction in long-term relationships than in hookups, then fewer long-terms relationships could lead to less sex. But this latter kind of research is also controversial in itself; longitudinal studies have a more mixed picture, with women's sexual desire dropping off after a while in a stable relationship. So it's really difficult to put all this stuff together with economics factors that may affect sexual activity through multiple pathways. In other words, it's easy to generally point the finger to economics as probably having something to do with less sex, but pretty hard to be certain of the (strength of) the various pathways.