The real reason these people died:
This was a case where a significant FLIGHT CONTROL PROBLEM was encountered on the previous flight. Significant enough that the pilot called "pan pan pan". Only a "mayday" is more serious than that. So what happened? Ground staff followed a checklist and swapped/tested some components and they looked fine on the ground. It's clear the pilots and ground staff did NOT know what was the root cause of the problem. But the airline got to make money, so screw due diligence: Over a hundred people were loaded on and took off to die.They had a FLIGHT CONTROL PROBLEM and didn't test fly the aircraft? Why not? That aircraft should have been grounded until it had been flown without passengers by a competent test pilot who knew ALL the aircraft systems including the MCAS.
Propose a new rule: If a commercial aircraft experiences a flight control problem on a flight and survives, it remains grounded after landing until (1) the flight control problem has been fully understood and remediated, and (2) a test flight (no passengers!) to normal cruising altitude and speed has been completed by a competent test pilot certified by the manufacturer. Any persons who are airline staff, management or engineer personnel who release the aircraft back to service without these 2 steps completed and documented shall lose all their professional accreditations and shall immediately be banned from working in the airline industry. Should the subject aircraft crash with loss of life, those persons should be charged with manslaughter.