Congress legislates the function of the FAA and oversees the funding of the FAA and has not been providing the funding required to keep the FAA attractive enough to hire enough people skilled enough to do the job they are expected to do.
FAA has always had a divided charter - to promote the aviation industry and to promote aviation safety. Clearly the FAA cannot do both and be effective at both.
I remain unconvinced that FAA would have noticed the potential that pilots would not trim an airplane because the stall warning was sounding at the same time. ODA or not, that problem was going to remain. FAA already accepted that a false stall warning could be sounded and stick shaker enabled when there was no stall.
Greater oversight by the FAA on the factory floor would very likely have called a halt to production out of Spirit a long time ago, avoiding the door departing due to out-of-sequence re-work, but that's a Congressional funding issue for not having enough FAA inspectors vs supporting Boeing and Boeing customers getting the planes sold and used to promote aviation.
Accepting so much discrepant material seems the bigger problem and it seems unreasonable that instead of Boeing inspectors in Wichita they had Spirit re-work teams in Renton.