I think conventional job interviews do allow you to target a broad range of competence, with a large margin of error, so if you were to compare Google employees to, say, State Farm line-of-business .NET application developers, sure, the Google engineers would outperform.
It's an interesting question whether a random sampling of Google engineers would outperform a random sampling of tech industry product developers from other companies. I don't know.
The bigger is, within the broad set of candidates that an interview process selects for, the conventional job interview is arbitrary bordering on capricious; it's inhumane for no business benefit.