[pas]

The problem was that because it was an unknown component its failure mode was not known, which created/exacerbated the panic.

There is a simple procedure, which is already part of the standard memory checklists. What to do in case of runaway trim. The pilots must/should be able to notice the trim wheels spinning, they then can disable trim motors and fall back to manually cranking them.

The problem is, panic makes a mess of almost anybody. Sure, pilots shouldn't be anybody, but we know how much cost cutting has been going on.

[rtkwe]

Well also the fact that the stabilizer can get trimmed far enough that the aerodynamic load on the rear stabilizer exceeds the pilots ability to move it manually. In that case the only real solution early in take off would be to re-enable the trim system so you could use the trim motors. The other solution to that situation is to nose down to release some of the pressure on the stabilizer so they can be manually cranked again, this isn't really an option early in the flight though because you don't have the altitude to slowly undo the erroneous trim while diving.

[pas]

I wasn't aware, and seemed quite ridiculous that there was not enough torque to rotate the screw, but looking at it, the angel of the helical threading is pretty steep.

https://www.netairspace.com/photos/N37474/United_Airlines/Bo...

And it turns out this can/happens even with the electronic motorized way, and there is a maneuver to work around the load. But it got removed from the manual...

https://www.pprune.org/tech-log/619326-boeing-advice-aerodyn...