People DO.
It's well known that most tech companies are ran incompetently. As you say, it's not the engineers' fault.
But most projects and hiring in these companies exists to juice promotion criteria. And that, depending on perspective, these companies are either massively overstaffed or massively underproductive.
The comparison to AI spending being wasteful holds up pretty well, these are companies that readily piss away billions in pointless spending.
I think it's a general problem, but in my rare conversations with execs nowadays, they seem rather uninterested in improving their decision making there. The actual performance of the organization does not appear to be all that relevant to them.
I don't know; I'm a Ron Popeil "set it and forget it" kind of guy. Make the dumbest, simplest thing that's going to work with some clear path for scaling. Then go do valuable things instead.
But in Uber's case, they tend to reinvent lower level pieces of platform/infra.
The idea of "if you add intelligence you make more money" is contradicted by the fact companies don't just always hire more people. Wy doesn't google just hire everyone?