They could, but not as easily. On the other hand, the FAA will look very bad if the EASA and CAAC don't agree with them.
This is what I think is going on:
Part of the 737MAX fundamentally is that 737 NG pilots did not need retraining to fly it.
That's a nice goal, but it is not compatible with MCAS. With MCAS in the picture, pilots need to fly out two situations in a simulator: (1) MCAS goes bezerk and they have to manually disable it, and (2) they get into the kind of trouble that MCAS is supposed to stop and then MCAS doesn't stop it.
I think Boeing is hoping they can do a software fix but not add a training requirement and I think that's a major reason why the fix is taking so long. I can't believe that regulators will clear the MAX to fly again without the training requirement. If Boeing is trying to avoid simulator training, they are doing a lot of harm to themselves, their shareholders, their employees, airlines, their suppliers, the U.S. Economy, etc. If they bite the bullet and accept the simulator requirement they can probably get back in the air soon -- they might have to pay for the simulator training that they promised airlines wouldn't have to pay for, but that's probably less than what they are going to pay because of delays.
Another problem with their foot dragging is that delays beget more delays. The more time they waste, the more new problems will be discovered, the more it will cascade. The fast way out is the way through, but from the beginning to this moment, Boeing has not appeared to recognize the gravity of this situation.
Could it be the case that Boeing is behaving obstinately as a negotiation tactic, perhaps to negotiate more favorable terms concerning who pays for the re-training? Maybe they recognize that retraining will be necessary, but fear if they admit it they'll have no leg to stand on when airlines demand Boeing pays for it. Or maybe they realize retraining to some degree is an inevitability but they're trying to minimize the breadth of that retraining?
But here's the thing, is it possible under current regulations to add on that training to existing pilots, without making them do everything else over again?
If they would have to treat this plane as completely unrelated to any existing model, doing an entire training program from scratch, then there is a legitimate need for regulatory compromise.
If somehow the FAA approves it while the EASA does not I can see the current US administration using the "Europe is protectionist" rhetoric. Nobody knows where we will go from there, I can only tell that then it came to car tariffs similar tactics used by the US seem to have "won", as I read yesterday that the EU is ready to eliminate tariffs on US car imports.
EASA is not going to approve the MAX for political expediency, the resulting scandal would end the existence of EASA. There is no tariff in the world that the US can apply that would convince the EU to commit such an act of self-harm.
Airbus just had an excessive pitch problem in the A321neo, nearly the same as the 737-MAX troubles. https://simpleflying.com/airbus-a321neo-pitch-problem/ Suddenly, the FAA might take aggressive action to ban that aircraft. Maybe the EASA doesn't really object to the 737-MAX as much as they thought they did.
CAAC would like smooth approvals for Chinese aircraft. Huawei is also having issues. Things could suddenly change after a day of golf at Mar-a-Lago. Lots of things could change, some quietly and some publicly.
I didn't say that either, and it doesn't matter. The problem is of the same general type. It's more than close enough. The FAA should be extra-careful, so maybe the A321neo will get banned. If the EASA wants to take a hard line on safety, they can hardly object.
After a bit of high-level discussion using that leverage, things may change.
These decisions, in all countries, are being made with consideration for international economic implications. The resulting decisions will be given technical justification as required.
We do not have details of this anomaly, but I hope you understand that some situations must be simulated, flying into them is difficult, maybe not possible, or downright unsafe.
I don't know how much about planes do you know (I'm starting to feel not much since excessive, maintained pitch during flare didn't tell you anything). But the context explained here is rare and obviously more manageable than "one of three redundant sensors failed and an aircraft went out of the sky without giving the crew even a possibility to save their lives".
EDIT:
Found new details. The pilot has to keep the excessive pitch although AWARE that he is stalling the aircraft.
This is what I think is going on:
Part of the 737MAX fundamentally is that 737 NG pilots did not need retraining to fly it.
That's a nice goal, but it is not compatible with MCAS. With MCAS in the picture, pilots need to fly out two situations in a simulator: (1) MCAS goes bezerk and they have to manually disable it, and (2) they get into the kind of trouble that MCAS is supposed to stop and then MCAS doesn't stop it.
I think Boeing is hoping they can do a software fix but not add a training requirement and I think that's a major reason why the fix is taking so long. I can't believe that regulators will clear the MAX to fly again without the training requirement. If Boeing is trying to avoid simulator training, they are doing a lot of harm to themselves, their shareholders, their employees, airlines, their suppliers, the U.S. Economy, etc. If they bite the bullet and accept the simulator requirement they can probably get back in the air soon -- they might have to pay for the simulator training that they promised airlines wouldn't have to pay for, but that's probably less than what they are going to pay because of delays.
Another problem with their foot dragging is that delays beget more delays. The more time they waste, the more new problems will be discovered, the more it will cascade. The fast way out is the way through, but from the beginning to this moment, Boeing has not appeared to recognize the gravity of this situation.