Correct
"I'm an effort to get engineers like the senior staff engineer to pull heroic feats"
I think this gives them too much credit. The reality, imo, is that the org had a pathological emphasis on "impact" and ran performance reviews so tight that everyone, managers included, were so scared of being PIPd and losing their grants that they were extraordinarily risk averse in planning and picking projects to bet on. And leadership in general undervalued "infra-y" changes as mostly make-work.
The turnover was partly because of this general effect - people scared, not betting big or smart enough, and optimizing for holding on / not getting fired. And to their credit, most of these people vested 2-3 years of their 4-year grant before it all fell over, so they made out decently lucratively, so maybe they're the real winners in all this after all.