Even after his infamous 2012 anti-gay parenting study was roundly and thoroughly debunked as BAD (biased, agenda-driven) science, if not outright pseudoscience, here he is five years later attempting to put forth a new, yet old and recycled, thesis about--what else?--sex. Here is the TL;DR version:
1) Three technological advances--the Pill, along with online porn, and online dating, but especially the Pill--has completely transformed the dating/marriage markets by driving down the relative "cost" of sex for men (hence the title). The "cost" has dropped to the point where the "cartel" is basically broken.
2) At the same time, and not coincidentally, women have also become less dependent on men, further decreasing the incentive to get married.
3) This is very, very bad because sex is a commodity, something that men basically "take" or "buy" from women in one way or another, and thus men no longer have any real incentive to get married nowadays. In other words, as the saying goes, why buy the cow when the milk is for free? (Which literally compares women to livestock, by the way, but I digress.)
4) Marriage rates are in free-fall (among young people, that is) and this is a disaster for society, because reasons. Same goes for birthrates as well--after all, we need more serfs to make the oligarchs even richer and more cannon fodder for their imperialistic resource wars, right?
5) Boys will be boys, and thus girls/women need to be the gatekeepers. Because science. Or something. Thus, women are to blame for being too "cheap" and "easy" when it comes to sex, and no woman is an island in that regard. (He barely even tries to disguise his slut-shaming here.)
6) And of course, the biggest losers in this brave new world of cheap and easy sex are women and children. Men too, but mostly women and children. Because they are dependent on men, so its bad when they become less dependent on men, because tradition. (The "concern" part of the trolling is located right here.)
Of course, he says these things with much more euphemisms and verbiage, and cherry-picked data to back up his specious thesis, but that is basically it in a nutshell. Note that he doesn't seem to offer any cogent solutions to this supposed parade of horrors--probably because deep down he knows exactly where that would lead, and it isn't anywhere good.
We saw what happened in the Victorian era, after all. An entire social movement was spearheaded to make sex as "costly" as possible for both men and women in spite of there being a surplus of women. The result? Prostitution and human trafficking, including of children, exploded--to the point where a whopping one in twenty women was involved in prostitution at any given time back then (versus less than one in 300 today). Talk about backfiring! And the notoriously lecherous Ancient Romans had quite a relative scarcity of women, albeit with an artifical abundance due to slavery of various forms--need I say more?
Even a return to the supposedly "kinder, gentler" patriarchy of the 1950s would not be any better, as it really was no golden age once you peel back the saccharine celluloid veneer of Leave It to Beaver and shows like that to reveal what it was really like. All of the widespread alcoholism, adultery, domestic violence, child abuse, rape, unsafe and illegal abortions, racism, and stuff like that kinda puts the lie to that specious claim. Stephanie Coontz's book The Way We Never Were explodes the myth of the "good old days" quite nicely indeed. True, the so-called sexual revolution of the 1960s and 1970s may have been a mixed bag as it were, but on balance we are ultimately all better off for it along with the feminist movement.
Honestly, one thing is for certain. The whole "commodity model" of sexuality is indeed dying, and that is a GOOD thing. Such an outmoded, outdated, toxic, and sexist paradigm is downright dehumanizing to both primary genders, and we would all better off without it. Sex is a mutual act, and it is time we started treating it as such. And marriage for economic reasons rather than love is becoming increasingly obsolete, as it should in an increasingly egalitarian society. And while marriage can indeed be re-purposed for a post-patriarchal society, the idea that everybody must get married as the sine qua non of "real adulthood" is outmoded and no longer holds any water in the 21st century.
Whether Regnerus and his ilk like it or not, society is nonetheless evolving, albeit in fits and starts. What is really dying here is PATRIARCHY. And women are gaining more and more power as men are becoming increasingly redundant in both the workforce and the bedroom, and soon they will reclaim their rightful position as the new leaders of the free world. Sorry, fellas, the truth hurts, but we will all be better off for it in the end. As John Mellencamp and India Arie famously sang, if you're not part of the future, then get out of the way.
Let the planetary healing begin!
UPDATE: Sociologist Philip N.
Cohen wrote an excellent rebuttal here.