Marriott's actions make perfect sense. Marriott realizes that its hard to be mid-tier after being top tier. Many people maintain status in multiple programs. I actively maintain in Starwood and Marriott, and passively in Hyatt and Hilton. At the end of 2008 I had easily requalified with Starwood but only had 65 nights with Marriott.

Had Marriott downgraded me to gold, I would face the very real prospect that my next 75 nights with Marriott would be without the platinum perks. As such, I would have been very tempted to drop Marriott and work on other programs such as Hyatt or even Hilton as I am currently mid-tiered with both. Achieving top tier in either would be a cakewalk by comparison to Marriott.

However, by extending my status, I no longer face the prospect of my next 75 nights as a gold. Since I retained my platinum status, Hyatt and Hilton are no longer tempting me. As such, Marriott will continue getting my business, which is generally over 75 nights each year. In fact I just spent 4 nights with Marriott this year.

To those who feel slighted. As the Marriott Concierge states, there are unpublished criteria by which a member may achieve or retain status. You have not lost anything that you were promised.