The big question is:
Does the money go to Firefox or to funny projects and (what I consider) insane exec salaries?
So yeah, find me a way to finance Firefox only, and not the funny projects, and to ensure that not a single cent goes to their execs (neither directly nor through some creative accounting, where they reduce engineer salaries to offset the cashflow from this new stream, and pocket the savings), and you have my 10 bucks a month for the next 8 years (and possibly longer, but let's see what they do in 8 years). I won't move the goalposts and I'll make good on my promise.
The usual counter argument in this type of discussions is that it's Google's fault, because they changed their sponsorship, and there's nothing the execs could do. And then the counter to that is why pay big salaries if there's nothing they can do about revenues. Back to square 0.
I wish Mozilla setup funds for each project like it was done for Thunderbird. Then the execs can be paid from sponsorships etc.. but I personally have stopped to give to Mozilla any money since that change happened.
If their revenue went way up, absolutely. Which is what happened when the executives got more money.
And then when the revenue goes down to something like $400 million, you'd expect something like the CEO stepping down and the number of executives getting cut. Like what happened with Mozilla.