Muilenburg is to blame. He got the stock price up by getting rid of all of the more experienced (older) higher paid engineers who knew to not make the sort of mistakes that were made on the 737-Max. I was a happy 35+ year Boeing employee who would have stayed where I was for maybe another ten years, but Muilenburg made my choice to retire very easy by changing the terms of the (retirement) plan to give me a compelling reason to leave. If I had stayed, I would have effectively taken a pay cut of about 20% because of the reductions to my defined benefit payout. Instead, I found a better job elsewhere for a 20% raise and took the early retirement.

I think part of that is, had there been different engineers there, it is not so clear that the outcome would have been different, but with different management decisions (e.g. whether to make a new plane or try to pretend it was still the 737) things could have been different.

Was the MCAS a lone example of rushed, poorly tested work done by people without enough knowledge of the industry they were working for? Or is it just the first one to come to light, because the MCAS caused the plane to be grounded before any others did?

We don't know, but my guess is, based on the other news coming out about the 737MAX since it was grounded, that there are other issues like this lurking. This tends to suggest that the problem is cultural, and the corporate culture is one of the primary responsibilities of the people in command.

To do good engineering, you need good engineers and you need a culture of good engineering. You need an organisation and incentives that encourage doing things well.

Looking at it through a software lens - even if you do have the best people, if your project structure squeezes development time, rather than producing solid code and catching all the bugs early, you'll produce flaky code that will produce surprises down the line.

Then on top of that, such will lose some of its best engineers (because they get frustrated) and probably won't attract new good ones because they don't value them sufficiently to pay them enough.