//The rogue allegedly was MCAS //
that's what manifested - but there's much more to it than that. boeing needed a quick competitor to the new version of the A320 - no time to design a new airframe, but the 737 airframe was not suited to the new breed of fuel efficient engines. MCAS was meant to compensate for the handling issues created by the engines, but boeing didn't see the need to tell the airlines about a system that was supposed to operate in the background. MCAS made the max perform/handle like an "old" 737 so the training upgrade required was minimal - e-distance learning and an online self-exam. of itself a faulty MCAS shouldn't have brought down a 737-max, the fact that the crews knew nothing of the system, never mind couldn't see what it was doing because the indicator was an "optional extra", meant when it went wrong, they had no clue how to deal with it.
aircraft design is expensive. training is expensive. any shortcut that will minimise both is too attractive to ignore. the FAA's "hands-off" approach did the rest.
the whole system is at fault, and it should not be imagined that airbus are any different. they've only been lucky because the A320 airframe design is 25 years younger than the 737.