At the end of the day the main problem of Firefox is that it fights against companies (ab)using their market power in one market to foster their browser on people. - Google: Try to use anything made by them with another browser and without a blocker and see how long it takes until you get the "SURF BETTER WITH CHROME"-ads thrown into your face - Microsoft: Edge is pre-bundled and you get little nags in the Google sty…
I agree that competing with these megacorporations on their playing field is unrealistic, which is why Mozilla needs to start competing in places where these megacorporations don't want to. Mozilla's marketing department has already realized that privacy is one such area, but their developers and culture still need to catch up with that.