Marriott launched its new loyalty program August 18, 2018 aligning the benefits of Marriott Rewards, Starwood Preferred Guest, and Ritz-Carlton Rewards. All accounts were moved over from the Starwood platform to Marriott.
However they kept all 3 program names, even though there were no longer differences between the programs. This has to do with contractual obligations. For members all that was left to wait for was the new program name.