> It's now fairly obvious MCAS was at the root of those two crashes. But, did it save lives in other circumstances?

Let's say Boeing ships a new airliner, where in 1/1,000 flights, the wings fall off for no reason.

Would you be asking the question of: "But did the wings save lives in other circumstances?"

Of bloody course, they did. Doesn't mean that they should have ever shipped an aircraft, where the wings fall off for no reason!

MCAS was a hack around a redesign of the plane. If the plane would have crashed at an even higher rate, without that hack, then the conclusion is not: "WOW, MCAS saves lives."

The conclusion is: "That airplane should never have been shipped, because it is a deathtrap."

If it would have crashed at a lower rate, without MCAS, then no, MCAS was not a net life-saver.

Boeing chose to redesign the place, making it more dangerous to operate. To mitigate the danger, they added MCAS, which was also dangerous to operate. It doesn't matter whether or not a MAX with MCAS, or a MAX without MCAS is more dangerous. What matters is that a MAX with MCAS is dangerous. Nobody put a gun to their head, and made them redesign their plane.