Right. There are two (very cursory) ways I think about these marquee DeepMind departures: these folks are (
are, not
were) amazing talents, but despite their capabilities they could not surmount some internal obstacles at Google that kept them from realizing their full potential. Or these folks were amazing talents for what they did in the past, but today those talents aren't able to get DeepMind to today's bleeding edge. Reality is it's probably a bit of both and there's just no nuance in the discourse so I share your fatigue.
And then I guess there's the third option which is money. These folks already have "enough" funds for generations to come, but there's a lot of financial fomo out there when you see all your peers becoming billionaires and you're a lowly centimillionaire.