I wonder the same thing... I have over 150 nights so far this year, not counting roll over nights, and I have only gotten a Concierge level room once. I know I should ask for upgrades but I don't feel like I should have to, it should be something that is just done when I check in. I am finishing my nights for the summer bonus and then moving on to another chain and will only stay at Marriott during bonuses. There is no real reason to give them any more nights.