> Personally, I think it was a mistake for many companies to try to turn software engineers into replaceable cogs in the machine instead of giving them managerial/ownership responsibilities.

It's complicated. Some companies give managerial responsibilities, but that still is a hit or miss strategy.

Your points resonate a lot with my experience as well, though I think most people fundamentaly don't like complexity and want simple answers.

A project costing "3 man/month" is simple. Hiring 2 more people because only 1 engineer is available to that project is simple. You don't need to dive into why this engineer would better fit this project, or how the cost would change depending on the order you do it etc.

Throwing money at hiring or consultants is a lot simpler.

To solve that conundrum, you need someone high enough to both understand the complexity, wrap into simple enough terms for the higher ups, deal with the internal politics to protect the team, and yet enjoy that position well enough to keep doing it day in day out. That's a pretty rare breed IME.