I don't get how or why it seems to have gotten worse in the last 20-25 years.

I was a very online teenager at the end of the 90s and I have formed friendships that last to this day. Or at least staying in touch. And it's not just me, it's the same for a lot of people I got to know offline who have different such circles.

Maybe because it was just a smaller circle of people? Maybe because it was so not normal that people were much more cautious? Or because half of the online venues were run by hobbyists? Or because no companies and bots and people trying to make money were involved. Probably the latter.