Boeing keep saying that the 737 Max will fly again ‘soon’ and have maintained this stance since it was grounded in March 2019. It appears that they have little idea despite being heavily involved in the processes required to return the type to the air.
Specifically regarding Boeing, I have little doubt that they could get the damn thing back in the air to everyone's satisfaction as early as last week, the delay is in finding a way of doing it which doesn't implicitly indicate that they fucked up bigtime in the first place (TWO attitude sensors as standard, ie not paying extra for the 'safe version', and also admitting that pilots needed extra training to fly the plane).
To do otherwise would lay themselves open to very expensive litigation (which to be honest, is probably, and quite rightly, a foregone conclusion now anyway).