Just to be clear, I think having to prefix my web searches is not a fix, but rather an even greater inconvenience. I'll either have to type "http://" dozens of times per day, or "g " a hundred times per day, for no discernible reason.
Aside from that I don't think Firefox is particularly good for the web. Their license is no better than that of Chromium, and Chromium has proven time and again it's a good starting point for a fork.
Mozilla employees are paid with search ad revenue, to an even greater extent (95%) than the subset of Blink developers employed by Google -- so their incentives aren't even any better.
Ultimately this is a super minor issue (and turns out there's a way to fix it, per the sibling comment), but everyone just has their own pet excuse why they "can't" change to a browser that is objectively better for the web in every way.
Tragedy of the commons, I guess.