I think it's more about transitioning from the founder-type CEO driven by vision to the maintainer-type CEO who only cares about pleasing the board to keep his position as long as possible.
Tbf while Cook doesn't have the product vision of Jobs, he does have a clear strategic/what we want Apple to be vision. He's a post founder CEO for sure, but one of the best and a different league from Pichai by all accounts.
Ballmer was employee #30 at microsoft.
While not technically a founder, he had been with the company 20 years out its 25 years of existence before becoming MSFT's CEO.
+1. It takes a certain kind of people to raise through the ranks like that, so you automatically filter out people who might be more akin to the original founders. Vision _might_ be an asset when rising through the ranks, but pleasing superiors, hitting metric, politics and luck probably overwhelm it.