The real question is how much is Reddit willing to pay third-party app developers for making the Reddit UX tolerable enough for people to stick around?
You're right though. As many people as there are fleeing, there are many times that who will stick around and endure whatever changes Reddit makes. Reddit will have plenty of eyeballs left to sell ads against. Now, will the people generating content and moderating still be around? What happens long-term if they aren't? That remains to be seen…
I had this discussion in here before and I think it's for the better that the majority doesn't leave reddit, for both sides.
The vast majority of redditors are lurkers. It's a small minority that actually care enough to post the content and engange in conversations. Coincidentally, this same minority is the only one that cares enough to leave so I am expecting the most engaging people to migrate to other platforms like this one right here and I expect that Reddit is going to be left with lurkers and no one to drive the communities forward.
Granted, they will still be able to sell ads to lurkers but who cares? That's not why most of us were in Reddit.
I was there to get more news and educate myself. If that's gone, I'm gone. I'm happy to do this here, as well.