The Max is not fly by wire, that's the problem. It's a hydraulic/mechanical control. That's why pilots aren't able to pull it out of dives or re-trim it, the aerodynamic forces are too much for the crew to fight against.
Right. If this was a fly by wire aircraft, it would have to have triple or quadruple redundant control systems and redundant air data sensors. But because the auto-trim system wasn't considered primary flight control, it didn't get evaluated like a fly by wire system.
Auto-trim has been around for years, and failures are usually more annoying than serious. But the 737 MAX's auto-trim had far too much control authority, and was being used to compensate for bad handling characteristics, making it a flight critical system.
And if they hadn't opted for secrecy, properly put it in the manual instead of hoping that the outcome of bad sensor readings would appear like that of a fried switch, someone might have realized what a perfect trap they had built while writing "engage trim cut-out, then work the manual trim wheel until you regain control or hit the ground, whatever comes first".
