To me there are two important factors that explain that:
* Dating apps, not good looking people have hard time getting any match on those kind of apps, so for those that use app and don't try to meet any other girls in real life I can easily understand that they don't have sex with any girls. Also these apps tends to increase expectations of people because they see beautiful people all day.
* Porno, porno is more and more present, and more and more flexible to people tastes, so it is not uncommon to find people be more happy watching porn than having real life sex
Not necessarily. There are plenty of sexual fantasies out there that simply can't be fulfilled realistically. Even with relatively common and safe ones it can be quite difficult for two people into it to find each other.
Isn't porn be it movies or books also available to women?
Riiight, but it is much safer for a woman to hookup on Tinder with a hot stranger than to watch porn like the nerds who absolutely preffer porn to actual sex do.
* Dating apps, not good looking people have hard time getting any match on those kind of apps, so for those that use app and don't try to meet any other girls in real life I can easily understand that they don't have sex with any girls. Also these apps tends to increase expectations of people because they see beautiful people all day.
* Porno, porno is more and more present, and more and more flexible to people tastes, so it is not uncommon to find people be more happy watching porn than having real life sex