As someone who is severely allergic to ads, I really don’t like this transition, but I understand why they’re doing it.

Mozilla seems to be facing a tough problem. How do you make money when your core audience isn’t enough to support the company, but you can’t realistically pivot to a new audience without kicking out all of the old users. Would it be better if Mozilla just faded into irrelevancy and focussed on developing Thunderbird instead? The FOSS community would have to continue to support Firefox, which would slow down development to such an extent that it probably wouldn’t be able to keep up with the rest of the web.