[alx_the_new_guy]

That can be sort of easily explained without selfishness/people being jaded.

Anecdotally speaking, I've met all of my friends through school/university/work, and all the friend groups I know of (so mine and my friend's) are basically same sex.

I don't think this is a coincidence. Getting education in tech, there were 1-2 girls in my class, by the time I've graduated it was one. Basically same at work.

So, neither I nor people I know have female friends to introduce others to.

Not sure if the situation is the same for women, but probably somewhat similar.

Also, approaching people is being seen as impolite in more situations these days, so less of that is happening.