For this specific case of MV3, I wonder how many of those developers are actually writing and maintaining extensions. Yeah, I know one suspected motivation of this change is disabling ad blockers but IMO even if we ignore this aspect this migration is planned badly everywhere. If they really wanted to focus on just kicking ass of ad blockers, it would be done much quicker without facing this level of backlashes.
Not just for MV3 (or even Google), but many of those "API teams" actually don't have a good understanding on its actual use cases so the incentives are usually aligned with their own goals and directions rather than the actual customers because what they see everyday is just their code base and some OKR. I guess they really didn't want to miss out the opportunity to clean things up so they put every single wish list into the bucket without much user study and then it's spectacularly exploded as we know.
I've seen a bunch of "internal migrations", which is supposed to be a way easier than this kind of external ecosystem migration. Unless it was planned and executed very well, those teams are usually shocked by the initial backlash and how "creative" their users are. Sometime those teams are able to come up with reasonable compromises, but in many cases they just deny the reality then blow things up (which sometime works if there's not much dependencies though, but many case it's just wasted as soon as upper managements kick in). This is why almost all successful API migrations are accompanied with some sort of extensive user study from the beginning rather than some arbitrary metrics/goals set by themselves.