Long story short, Boeing put bigger engines on their 737 Airframe to cut costs. To make the pig fly they also had to change the position of the landing gear, and a new electronic [lets just call it a flight assist software] because the aircraft was so difficult to control under certain modes of flight.
So it's like the difference between a Cadillac Escalade with ABS and traction control, ESP and one without ABS and ESP. Easy to lose control of an Escalade without ESP and ABS.
They used the Angle of Attack sensor to tell the computer to pitch the nose down if the aircraft was at a stall angle. Problem was, the sensors fail/give bad readings.
Furthermore, the pilots flying the 737 MAX should have had training for what to do if the AoA sensor malfunctioned.
So these pilots didn't have the training to cover this scenario, the airline didn't buy the "upgrade" which consists of a redundant AoA sensor and a new light in the cockpit that says the AoA sensors don't agree.
So once again, American engineers who don't know what they are doing, build on the work Americans did when we did have decent engineers [before our schools were totally indoctrinated by Marxist Ideology] and this generation of Engineers fall short of the mark.
We couldn't build the F-16 with the retards we have today. Look at how we fell on our face with the F35.
This crash is a story of corporate greed, incompetence, and the failure of the US Education system which is no longer turning out competent engineers.