Discussion quality is, in my experience, mostly a function of group size. Online discussions scale better than in person, but there's a limit.

One thing I do miss from the early internet was less anonymity being the norm on Usenet/forums/etc. Discussions tend to stay more civil when both parties know there's a "real" person on the other end.

Otherwise, my memory of early 90s internet supports exactly your conclusion. There may have been better opportunities for small discussions, but big ones devolved the same way they do today.