Hegemonial sexuality has always been by the numbers, there's entire modes of seeing that people get indoctrinated with from a very early age, way before they start consuming porn (if they do that at all, a lot of women, especially older ones, don't and we are still deeply affected by this). Actual heterosexual desire is entirely buried under cultural conditioning and that's by design. Because in a capitalist system, sex does not actually exist for your pleasure, but as a reproductive function and a control mechanism.

Also if there's an "epidemic of asexuality", it may be because a ton of people are actually acespec and are only now realizing that this is an actual thing that exists. We live in an allonormative society that presents perpetual hornyness (or at least very reliable availability to your partner) not only as the default, but as the only "healthy" option. Any deviation from that is pathologized as a dysfunction. People are forced to be oversexualized and nobody can say at this point how many people do not fit into that mold at all or only partially. If i had to hazard a guess, i'd say there's not that many fully ace people, but a very sizeable percentage of the population may be what's described as demi or greyace and we just don't see it because men are required to be always ready and women are ... kept in this constant double bind state of hornysuperposition where we aren't really allowed to be sexual beings, but simultaneously aren't allowed to be "prudes", either. Sexual liberation has been entirely about the right to be more horny, or horny in different ways. That we may not care as much about fucking as the people who want to fuck us want to make us believe is only now entering the conversation. Just as with bisexuality and nonbinary identities, we're atm only seeing the tip of the iceberg with this.