Source: Ex-googler.
What does "peer cannibalization" mean?
I know of two groups (one of maybe 10, and another maybe 30 engineers) that sat essentially leaderless for several months each before Google hired a manager from outside the company. Neither one of these, in my opinion, have a good handle on Google culture.
There is no real reward for becoming a manager (no more pay, no more level, no more nothing), but a lot of hassle, so very few engineers want to do it.
At least that is what I see from my limited vantage point.
Source: personal experience circa 2013-2015, when I was there and trying to transition from individual contributor and tech lead to first-time people manager. Of course I wasn't considering executive roles like this article is about.