There is always a spot for more managers, welcome to big corps.

Its Managers all the way down...

until big corp laysoff all that middle management

and middle managers start their own firm, consisting entirely of manager managers

Replacing managers is a walk in the park compared to replacing programmers. The focus is on programming because that is the benchmark, if we can outsource that to AI, then we can replace everyone.

Well maybe more project/program management than typical people management - you still need someone to organize the work at a higher level, collect the requirements and feedback, check all the compliance boxes, etc.

But I agree that typical line management jobs will evaporate along with the engineering ones.