Count yourself lucky
Well at least you are not like us Aussie Cent where we need 25 stays or 50 nights to keep our plat SPG.
I think it is best for every Cent member to work out how much their Cent is costing them vs. the value of the benefits (ie. upgrades, etc). If the value of the benefits are less than the annual fee, MOVE! We are better off using a 'normal' card and just pay for the 'upgrades' that we want ourselves.
If anyone from AMEX is reading this, don't say you haven't been warned! Amex Centurion is sliding........