It's quite easy to flip this around: forcing topical discussion through groups are just a workaround for lack of proper discovery and aggregated search...

To give you one simple example: I get a lot more useful and meaningful interactions from following #emacs on mastodon than by waiting for people to find out and post to !emacs@programming.dev. Same thing for #nfl and !nfl@nfl.community or !nfl@a.gup.pe, etc.