Earlier quoted context omitted.
The problem, from my perspective, is that I (as a candidate) have certain things I want to work on. You might have something I can do, but is it something I want to do? I don't want to be hired into a general pool; I want to be hired for one of the specialties I am interested in.
The problem is that what interests you now may not be economically valuable next year. They want you there past one project, because the future is too murky to guarantee your current role will continue to be needed. Google et. al. are hiring generalists because they want people of a mindset such that when the entire special-purpose they hired them for dissolves, they're willing and eager to ramp up on a new project a…
I get that there are people who don't care (much) what kind of code they are working on. If those are the people Google exclusively wants, that's fine. I just won't have a place there. I do not think this is a generally-advisable strategy, though, as the GGP I was responding to indicated. In fact, I'd argue that well-crafted teams of specialists are superior to, but harder to staff than, teams of generalists.