That said, perhaps moderators and users should be willing to admit that Reddit produces some of the value here. Every voice I've heard is, "we do all the work", "we produce all the value". It's also comical to hear moderators say that when the users of their subreddit could make the same claim trumping the moderator.
Right now the mods seem to be flexing their muscle, showing that Reddit has allowed them too much power, rather than showing the actual need for an api. In all of these discussions, I haven't seen a single video detailing side by side how necessary the third party apps are. Just claims that everyone needs them and uses them.
Reddit, of course, seems hell bent on making their UI worse and worse. I don't know what their play is or how they plan on getting paid for it. I have to say, though, for a free product their ads are among the least intrusive I can think of.
Every subreddit is just a click away from moving, though. I see some doing it. But a lot of those subreddits enjoy the influx of users that reddit brings them (until they don't, of course).
Very little, and almost none from a technical POV. What value Reddit does provide is a side effect of 17 years of investments by users, their communities, and those communities' unpaid moderators.
Yes, Reddit is free to attack the foundation of their value for short-term gain. However, the reality is that Reddit has never been easier to replace than it is right now. If even a relatively small percentage of users/communities/moderators take their toys and go elsewhere, it could trigger an irreversible decline.
I don't think this is the biggest threat. Twitter, being a unitary platform, mainly has to worry about other platforms, or protocols that masquerade as single platforms.
But Reddit is built up of many communities. The 17 years of history is pretty valuable to Reddit, Inc, of course. Lots of long-tail search eyeballs. But the people actually generating that valuable information are generally focused on the latest discussion, not the history. I think the threat here is the various communities going other places. One by one or in pieces, scattered across many sites and tools.
As a proof of concept here, look at patriots.win, birthed from /r/The_Donald: https://en.wikipedia.org/wiki/R/The_Donald#Patriots.win
It's just not that hard to set up an online forum. Reddit captured those many communities because it was even easier, and because Reddit Inc acted as good stewards. We'll see how this plays out, but I could easily see Reddit being permanently diminished due to its execs unintentionally triggering an open-web rebirth of the independent forum.