My memory is fuzzy here, but wasn't it the case that even with training, you only had a window of a few seconds to disengage the MCAS before the aircraft became

My memory is fuzzy here, but wasn't it the case that even with training, you only had a window of a few seconds to disengage the MCAS before the aircraft became unrecoverable? If you waited too long, it cranked the jackscrew to its extreme position, and there was no way to un-crank it with the MCAS disabled (i.e. MCAS had exclusive control over it). That seems like an unacceptably fragile failure mode to me.