Too busy asking people to invert binary trees and not looking for people that know how to make products that make money.
Eric Schmidt, who is an exceptionally rare talent understanding engineering, business and politics at the same time was changed to a person who just want to show more ads (the product that makes money) with 0 engineering background.
The best are / were there before they quit to create companies, like OpenAI because it was easier than changing management.
Also I bet Sam Altman would be able to reverse a binary tree (it's a trivial recursion) even if he was never at Google: it's just part of being a professional programmer.
There's also this gem of how google wanted one of the creators of C to take a C test https://www.theregister.com/2010/04/21/ken_thompson_take_our...