Reddit sadly went the way of mostly write-only microblogging a long time ago now. I'm not sure what the solution is between invite only subs or heavy and time consuming moderation, and random comments that are just people thinking out loud, as using any sort of karma metrics would be useless when you can get 20-30k off a no effort post in a popular sub, but I also doubt that reddit the company spends much time worrying about it.

I can't remember who I stole "the internet is write only" but it's felt very true as audience size exploded.

Perhaps the worst part is that it's self reinforcing in either direction, and few people ever leave the agora unless they delve into niche subjects, so they bring the agora mentality with them.