Like, it's probably more noticeable that you don't have any romantic or sexual relationships than it would be if you don't have any true, close, platonic connections. Romantic and sexual relationships have things that are very obvious and for the most part, exclusive to them, such as kissing, making out, sex, etc. Platonic relationships that are true and close are not as visible, they're more feelings on the inside (not to say that there's none of those feelings involved with romantic and sexual relationships). If you look exclusively at the activities done with a platonic friendship, it's not very different from an acquaintanceship, or an activity partner.
I've met people who claim they have friends, but they're just coworkers they talk to a bit, guys they play games with, or guys they see at the sports bar a lot. Not people who actually support each other or any true connection. Now granted, there's nothing wrong with having those acquaintanceships or activity partners, and it can be argued that they're necessary for a fulfilling life, but they're not the same as a true connection or friendship. If you've never had that or hadn't had it in a while, it can be hard to tell what that feels like.
The only way to make these connections is through social skills, which a lot of people lack. They lack social skills, so they don't make connections, platonic or romantic. Since romantic and sexual connections have more exclusive activities, it's more easy to notice them than the lack of true friends. So I'm wondering if all this talk about the lack of romance and sex is really just poor social skills.
Thanks. It's always a tricky subject to break down because there are clearly examples of people who are "good at socializing". But historically not everyone, not even close, was like that. People were socialized out of necessity, at the most basic level it increased odds of survival as long as food was secure. Homo sapiens are specialized through evolution for cooperating and socializing, which is why some groups of our species dominated the planet and achieved the things they have (without making value judgements about those things or how sustainable any of them are).
Group, and self-, interest are the friction in the socialization process. Everything about capitalism promotes self-interest so the reasons why socialization would decrease are numerous and obvious. A side effect is the loss of the interpersonal relationships that almost everyone would prefer not become transactional, friendships and romance, which were usually fruits of the other activity which socialized people.