What is worrying is that there could be many other potential sources of failure which simply didn’t trigger because the MCAS situation was so bad it led to 2 plane crashes before they even had a chance to bring down some planes.

In other words, if you have 2 bugs, one with a 1/100 chance of triggering and the other with a 1/1000 chance of triggering, by the time you hit 500 attempts, odds are the first bug triggered twice, while the second didn’t even once. So you solve the first bug, that still leaves you with a problem that has a 1/1000 chance of triggering, when the expectation is that bugs should only trigger at worst 1/10000 times.

Solving the MCAS issue is not by itself a reliable indicator that this is a safe plane to fly, especially since we know there are many fundamental procedural reasons to be worried about the quality of the plane.