However lifetime status in the new program is determined, I really hope that Marriott put some thought in how to keep their Lifetimers engaged, staying and spending.

This is one area where SPG hasn't excelled : Lifetimers have tended to be excluded from targeted promotions, and without the need to chase stays and nights to renew status, there's less incentive for their 'best' customers to put incremental revenue in Starwoods pocket.