While I normally detest simplistic evo-bio approaches to complex emergent social behavior (particular as it is frequently used to justify shitty, misogynistic behavior), quite a few of those examples could be chalked up to evolution taking a slightly longer view than "get everyone pregnant all the time".

There is probably a strong reproductive advantage for a population as a result of having reproductively disinterested members, and there are individual benefits to sex and sexual desire outside of it leading to pregnancy.