Perhaps Amazon has changed, or AWS is simply different/better in this regard.
Besides, it sounds like the resource he's particularly interested in is compute (and maybe storage) and AWS has this in spades...
The compensation was ok at the time, but starting to lag their peers by the time I left (within a year of leaving my comp had a little more than doubled). My understanding is that they've made an effort to catch up there. Regardless, Pittsburgh is a staggeringly cheap place to live (I grew up there) while Seattle is decidedly not (I live there now). Unless he's tripled his comp, he'll be making effectively less. That wasn't my point, though, I assume he's not moving for the money.
I was actually talking about resources to dedicate to research.
What makes you think Amazon will be willing to supply compute (assuming they actually have substantial excess cycles to sell, particularly on GPUs, FPGAs, or ASICs) to internal development efforts? Simply having the resource doesn't mean making it available. Actually making appropriate resources available to people trying to solve problems would run completely counter to my experience there.
As the lab head, I imagine he won't have a hard time getting resources--they must have given him something like a startup package to lure him there.
As a big name, they have a strong incentive to keep him happy: if he were to leave in a justifiable huff (e.g., "they promised me tons of compute and all I got were these Fire Phones"), it would make recruiting much harder.
Unfortunately, moving because you believe Amazon will throw resources at a problem shows a distinct lack of familiarity with the "frugality" aspect of Amazon's culture.