> But with Reddit, it's the only forum left (for any number of broad and narrow topics) so you're either there or nowhere.

Reddit wasn't even that good as a community space in the first place. It was a content aggregator with user-moderated comment sections, and those make for pretty awful communities because on anything remotely controversial you get factions dog piling each other trying to hide each other's posts.

That said, communities are all on discord now, and quite honestly I think it's for the better. It gives moderators a lot more discretion, but balances the scales by making it very easy to create new servers where one can invite like-minded people and grow organically.