As you say, Reddit has slowly been transforming into yet another social media site. Maybe federated protocols (ActivityPub like Lemmy/Mastodon, ATProto, etc) can win out. More and more of my topically focused conversations these days happen on Matrix and Discord. It's much more like IRC than forums, but it's generally much easier to stay on topic and the smaller crowd sizes make moderation a much simpler process. I'm also just fine with folks like us scattering into niche spaces. Our interests are niche, our habits are niche, a niche space suits us more than the "social media mall." (I also do use social media for more social media like experiences, but I consider that to be separate from chatting topically about my interests.)
I'm goin' back to /. where CowboyNeil at least warned us when he was going to do something stupid.
I use maybe 2-5 subreddits at this point because Reddit has rotted out so much. At least half of those are shutting down permanently as a result of the API changes, and the other half are participating in the blackout. I don't need a shared account across all of those services. In fact, I tend to visit subreddits individually anyway so I don't have to guess about the context of every post.
None of my favorite subreddits rely heavily on photo posts, which keeps hosting costs low. In fact, I notice a strong association between quality and text-only subs, likely because it keeps the lowest quality memes away.
It might not work for every subreddit -- I don't anticipate the denizens of /r/funny would embrace a web forum -- but for hobby, book, and series-related communities, web forums have been around a whole lot longer than Reddit. Reddit only took over because it was marginally cheaper and easier to host; if mods lose their useful mod tools and power users lose bearable and efficient methods of browsing, forums start to look mighty attractive again.
This is good or bad depending on who you are. If you're a user who went to reddit to have conversations with people online, it's bad. If you're that user, this API change and loss of 3rd party apps is yet another nail in the coffin.
If you're a newer user (~5 years) who came to reddit for its social media experience and just want a feed to scroll with memes and pictures of cats, this is API/3rd party app drama is entirely irrelevant to you. This is now the majority of reddit by far, which means reddit the company is just fine.
There's nowhere to go for us classic forum people. There is no equivalent to 2013 reddit. I'm would love for this to be a kick in the ass and to be enough to jump start alternatives, but right now I'm not optimistic. Too much focus on decentralization etc. which I think introduces too much friction for not enough gain.