How to kill people by saving money, episode #28066
If we go to root causes, the whole reason that Boeing added MCAS was because it made design changes that in any other case would have led to a need for pilots to re-certify on what appeared to be the same airframe (the car analogy is not far off - what Boeing did significantly changed its flight dynamics). That would have made it much harder to sell (associated costs and lag while everyone got up to speed), so MCAS to the rescue.
The problem is that MCAS, for all its critical functionality, appears not to have been coded with much in the way of redundancy on sensor input, and a critical error in assessing trim made that its changes were cumulative and thus had a far greater impact on trim that was intended. Add to this an inability to kill it when it became problematic and you have the recipe for the disasters we have seen - it also demonstrates that grounding the planes before we had a third crash confirming a suspicion was the right call (not that I think that should ever have been a question - there are some stiff questions here for the lag in the US that carried the potential that one of these planes could have dived straight into a densely populated area).
These changes and their fix handily bypassed any critical eye asking intelligent questions by the way in which the FAA changed its approach to certification - the latter is now being investigated, and the political climate in the US makes for an uncertain outcome at best. This FAA thing may lead to another disconnect - there's no redundancy in the safety that the FAA used to provide, and with the changes in approach that have now laid bare I can see it quite possible that other nations may start looking at making this a tad more independent.
My fear is that this will spawn becomes a political battleground that has everything to do with power, much less so with our safety (as always, that'll just be the excuse).