They don’t really have a choice. It’s upstream Chromium that’s doing it. They don’t have a big enough development team to fork Chromium and continue to support Manifest v2 extensions. Plus, I believe that Google will be removing those old extensions from the web store.
Their own tracker and ad blocker will continue to work. I know you can load various block lists. I just use uBlock Origin, so I’ve never really dug into their built-in blocker too much. But from the complaints, I don’t think it is as good, but they are continuing to developit.
Firefox uses their own browser engine. So they can support whatever they want. I’m not sure if they have any other options to change.
But I’m pretty sure every browser that is based on Chromium will have to do what Google decides. I’ve heard some others might try to keep support for a few extensions, but I have no idea how well that will work.
