Boeing, if you ask me, committed a cardinal sin in aerospace. They cut corners, ignored redundancy, lied to regulators and as a result directly caused airframe losses killing crew and passengers. And that after decades of efforts to increase safety. All that just to save money and maybe keep market share.
Had they just done all the proper testing and development they did after the aircraft losses upfront none of that would have happened.
This is a textbook example of how the most expensive point to make a change is after the product ships.
An extreme example, perhaps, but a good one.
There's plenty of blame to go around, up to and including the society that says it's ok to not pay a living wage to the working class because "infinite downward price pressure is good for consumers" (until they die in a plane crash, that is).