That is because Amazon and Google are looking for replaceable parts. So my experience has been in data science, suppose I apply to Google, get an interview (extremely likely to be with one of the data teams), I can in theory after the interview move to a front-end team or a team that works on Go. This is not a bad thing. This is not a good thing. It is however why large companies work the way they do. The thing to realize is that this is not a process that a small company needs to roll by.

(Of course, there are silly things that Google does like ask potential Product Managers algorithm questions; I am not clear how that helps.)