You're kidding right? Google's average employee is almost assuredly more capable than top performers in almost any other company. They probably have more actual "head of the class" people than any other company on the planet.
Googlers are more capable than other top performers? Well, yes, but that comes with some gigantic caveats.
The main thing Google has been consistently great at is designing algorithms and systems to process large amounts of data efficiently. You can't take that away from them, of course.
But that's one of the smallest parts about building beautiful software.
When it comes to other important things: understanding how to build products that are loved(particularly in the social space), or understanding the human element, they've been woefully inadequate on a comical level.