Pretty soon, people became lazy. Pretty soon, people stopped having sex with each other. Sex became a very private act. The feeling of someone’s palm on your skin, or their hair in your mouth, or their toenails scraping your knee were universally understood to be distracting and intrusive.
I find this branch of this particular universe to be very hard to believe. I can understand how this shift away from sex being a physical to private connection being related to shifts as a result of the apocalypse. However, since the beginning of time, human beings have been intrinsically motivated by physical contact and connections. For this type of primal desire to disappear is confusing to me.