Reddit has been pretty good at not walling off content, but think of all the forums that died and went to hell, being tortured in the afterlife as a facebook group, where all the knowledge people spend time writing down, all the questions being answered, are trapped in the facebook ecosystem, where it's close to impossible to find. This is by design too I believe. I used to be a mod on a hardware forum and we had rules that you needed to search before asking. The opponents to this rule said, that if people just searched, then the forum would die out (it didn't) and I'm quite certain that information on facebook is hidden away, to keep engagement going, by having the same shit being asked and answered over and over in perpetuity.
I like the idea of going back to forums, but with the added benefits of federation. It's the best of both worlds in my opinion.