Google is an "elite" company, almost every engineer there would be one of the best hires any other company could ever make. Generous compensation is one aspect to accomplish that hiring goal (amongst other things)
Not true - they just lived through the interview process. I remember working with a former Google engineer at a startup who flat out told me that I was a better engineer than him.
It's harder to see who will be amongst the best engineers early on in someone's career. Each person develops their abilities at different speeds & times in their lives.
I'm going to say that's a huge stretch.