So, let me build a tiny timeline and speculate a bit. A lot, actually.
Four days ago FAA Administrator Stephen Dickson met with Boeing CEO and former Chairman Dennis Muilenburg. It was Friday. And something was said at that meeting so bad that Muilenburg cancelled his weekend of golfing and prioritizing safety and sped to Chicago to cease the 737MAX production. Considering that China demanded full re-certification, I think Dickson told Muilenburg that 737MAX would never fly again. Right now Muilenburg and Boeing are "boiling a frog" and waiting for their year-end bonuses to come through, after which they will declare the end of the program.
PS Can we on pprune agree on and adhere to a simple English language rule that a person or a machine that's underwent certification is called "certified" NOT "certificated"? I just can't stand that non-word anymore.