I was mostly commenting on the "broader trend" aspects and the assignment of primary blame to implementing engineers.

There's another problem with Chrome, which is that nobody is actually paying for it. So the big corps move features along there only in the sense that they won't adopt it or will drop it otherwise. I don't think the big corps are pushing for Mv3 but they also probably don't care that it arrives either. Conversely, I wager Google estimates nearly nobody will revolt and leave Chrome over the loss of Mv2. It hurts ad-blocker developers and it hurts the most conscious users, but Chrome is a marketing product targeted at mass adoption first and foremost. I personally hope their estimation is wrong and the current browser monopoly breaks, but this may not yet be the breaking point.

Even if that happens, Chrome eagerly adopting enterprise policy support may keep it on life support in that environment, though.