The Internet of open forums and discussion boards was the one where people wanted to share, not hoard. It was a culture of "pay it forward", "growing the pie", "rising tides lifts all boats". A culture that gave us Wikipedia and StackOverflow and all the subreddits that make people append "site:reddit" to their Google queries. A culture that enabled free and open source software to exist, and transform the world. A culture of openness, a culture of hope.
What you described is a culture of fear. Fear of spammers and marketers and adtech companies and other evil scoundrels - entirely reasonable on its own, but also suffocating. A culture of hoarding, a culture of closedness. A culture of not giving a fuck about the wider world. This change, as mediated by technology, is only possible because of the openness that came before - it's literally built on Wikipedia, StackOverflow, and heaps of FLOSS. It walked up the ladder, and is now pulling the ladder up so others can't follow. This new culture will not give us a new Wikipedia or StackOverflow, but rather let both of them wither and die.
On another, somewhat unrelated note, prompted by an earlier discussion on a different thread:
> I'm part of a few discords where there's a lot of valuable knowledge about purchasing certain consumer products. If this content were discoverable by millions of people it'd be someone's full time job to game the system.
That's nice, and I'm both happy and envious. But it's ironic that doing things this way is considered clever and good, even though it's terribly exclusive - yet individuals exploiting their knowledge and skills to achieve the same by technology are considered a problem that needs to be stamped out for the sake of equality. As always, it's not thinking but socializing that wins.