I assume most of this has to do with the fact that they were already processing user data in the form of tab/bookmark/profile syncing and their pocket integration. Some lawyer probably pointed out that they didn’t CYA enough with their original terms of use.

For now I’m sticking with Firefox since they still support manifest v2 and proper ad blockers and I don’t want to contribute to the Chromium based monoculture on the web. If Mozilla really does turn evil I’m not sure what I will switch to.

Edit: I do worry about the future of Firefox if Google is forced by the courts to stop paying for being the default search engine.