Three of my friends (all similar backgrounds) interviewing at Google this year have had completely different interviewing experiences. One even bypassed the phone screen and was flown to Mountain View for an IRL technical screening/interview. These are all for the same role.
How does your data reconcile that?
Is it: You think they should have had exactly the same experience/path?
Regardless, any of the points i can think of don't really seem that relevant to your original point and my response.
Did you respond to the wrong subthread?
I'm providing an example as to how it is inconsistent (friends experience) as well as an a priori rationale for why it's arbitrary (e.g Googliness is a fuzzy criterion that allows interviewers to make any arbitrary call).