Boeing appears to have kept very quiet about the MCAS for a reason, with barely a reference to it anywhere. Why, would it have jeopardized the grandfathering of type certification?
That is precisely the question that ought be asked.
Somewhere buried is the reason to stay quiet and it has little to do with the pilots don't need to know, but it is perhaps something that the corporates preferred the regulator not know, at least prior to certification.