To return to the OP's question and topic at hand, qualified Marriott members should expect Ambassador status and access/benefits to start whenever the new loyalty program becomes active sometime in August.

The martyrdom and hypocrisy of some Marriott elites in this thread is startling. it is hypocritical to complain about the start date for Ambassador benefits while simultaneously questioning the value of the Ambassador benefits. It is martyrdom to complain that Marriott elites have to wait longer to get something that Marriott never before offered. And anyone who wants to pretend that the current Marriott "Ambassador" experiment is anything remotely close to the SPG Ambassador experience is kidding themselves.

I think it's obvious to anyone paying attention and who isn't entitled that Marriott elites who stay 100+ nights are thrilled for the chance to possibly qualify for Ambassador status--which is precisely why so many want to know when they can get it (the nature of this thread) and how to spend the $20K with the 100+ nights to qualify for it.