I'm not sure why you've edited your response rather than responding. It's a minor system. There is no firm evidence yet that it was responsible for this crash

I'm not sure why you've edited your response rather than responding. It's a minor system. There is no firm evidence yet that it was responsible for this crash other than some ADS-B data which only really shows that the aircraft was having control difficulties. Pilots are trained not to get near the stall. Unless something has gone seriously wrong an Airliner will never go near that region of flight in normal service. Most airliners have stall behaviour which is likely to enter a spin or otherwise difficult to recover from, that is why most are fitted with stick pushers which prevent a stall ever occurring. There are lots of other systems which can control trim on an airliner (the Mach trim system, the auto autopilot etc). Each of these have failure modes that can lead to a runaway trim situation. The MCAS system is trivial. It may have a flaw which led to both of these accidents but it isn't the world is falling and Boeing tried to patch it with different software.