Agreed. As I recall, EY posted at one point that prior to thinking about existential risks and FAI, his conception of an adequate life goal was moving the Singularity up an hour. Sure doesn't sound like he anticipates single-handedly making an FAI.

At best, he will make major progress toward a framework for friendliness. And in that aspect he is rather a specialist.

Agreed. I don't know anyone at SIAI or FHI so absurdly overconfident as to expect to avert existential risk that would otherwise be fatal. The relevant question is whether their efforts, or supporting efforts, do more to reduce risk than alternative uses of their time or that of supporters.