Boards are often toothless though, just look at Tesla's.

Replace the C-suite. This is done frequently in M&A's and other corporate strategies in extremis. Fire the guys at the top and replace them with people with good track records.

You can rotate people in and out of the C-suite, but incentives and culture aren’t going to change. These people are largely figureheads that get paid a lot of money because they are Ivy Leaguers whose friends on company boards who set their salaries are all Ivy Leaguers, too.

It’s not like Boeing is going to get a new CEO and then suddenly middle management is going to start prioritizing safety, engineering rigor, and risk management over profit.

Counterexample: Nadella

If the new CEO doesn't want to go to jail, then they'll make the changes.

Who do you think sets the incentives?

This conversation is so weird to me, I don't get what people are arguing: is the argument that it's better to replace middle management than top level management? That we shouldn't do anything? What?

You would keep the status quo. The problem with Boeing is the replacement of a strong engineering-first culture with a profit-first culture over decades. It's a classic playbook: acquire company, erode product quality and culture for profit, pay out shareholders, discard hollowed-out husk.