In this case you're proposing to punish the smallest cog in the machine, some middle-manager or executive at Boeing.
It would be just as logical to throw every single American in prison for around 45 minutes (~1 person dead in 737 MAX crashes for every million Americans, 80 years (let's call that life in prison) / 1 million =~ 45 minutes).
After all those are the people responsible for electing the people whose job it was to oversee Boeing. Shouldn't we blame them for their disinterest in the activities of the FAA? Maybe give people who complained about the FAA's rubber-stamp regulatory policy before the 737 MAX parole?
All you'd accomplish by throwing people in jail is to incentivize these companies to restructure decision making to be more diffuse, and make all subsequent air crash investigations much more difficult due to everyone involved being afraid of having made some prison-worthy mistake.
Because the usual argument is that the C-suite and especially the CEO are personally responsible for the successes of a company.
So it's not unreasonable to hold them personally responsible for the failures too - especially when those failures amount to suspected criminal negligence.
This is not the same as assuming guilt. Due process should still apply.
But the risk of personal liability should absolutely be present as a deterrent.
And if some executives don't want to operate in that environment - that's absolutely fine. The system should encourage responsible actors, and allow the removal and punishment of those who prefer to act irresponsibly.
These people make tens or hundreds of millions of dollars in compensation, truly obscene amounts of money compared to the workers they manage. Why should they live risk-free lives when the lives of so many people rest on their decisions in the C-suite office, and their decisions are clearly not made with safety in mind, but rather profit?
Your argument is like claiming that a taxi company owner should go to jail when one of his drivers rapes a passenger, even if there was no way the owner could have known the driver had this propensity. It's totally nonsensical.
The executives at Boeing are the ones ultimately responsible for the decisions that led to these crashes, because they prioritized profits over safety, and directed their engineers to work towards that end. For that, they should go to jail.
The root cause here is "Boeing management wanted to get a plane out quick so they didn't lose market share". The way to examine the system and make sure this doesn't repeat (for now...) is to put someone in jail for it. Then the next time that some plane company wants to cut corners and get an unsafe plane out quick, some manager who doesn't want to go to jail will put a stop to it.
Show me the flaw in my logic.