Which is useless if your bank shows you an empty page with a message that says they only support Chrome and Edge "for security reasons".
And Mozilla had many, many, many chances to endear themselves to developers. Their actions can best be summarized as they don't give a damn. It took them years to ship basic dev tools with Firefox. Then they wiped out an extension ecosystem that had been growing for more than a decade with the justification that they needed to get rid of technical debt. Meanwhile, Firefox still contains bloatware like Pocket. As for the privacy argument, Mozilla's track record on privacy is mixed at best, considering the many questionable choices they made in this regard in the past.
"The answer to all this" is not Firefox. Not the Firefox made by the Mozilla of 2022, anyway. If the Mozilla of 2004 could somehow be resurrected, perhaps they could turn Firefox into something that would indeed be "the answer to all this". At that point, developers wouldn't need encouragement to switch to Firefox. They'd do so simply because it would obviously be the better browser for them.