None of the regulators investigating MCAS and its consequences seem to agree that it can be easily fixed, mostly because they don't believe that the stes you outline would result in a safe and effective system.
You presume to know what the world's regulators are thinking? How arrogant. All the discussions are behind closed doors. Were you in the room?
Don't confuse their requirements of evidence that the problem has been rectified with them considering it anything but a simple fix.