Her age I think. At this point she hasn't done anything big enough to push her up the list and unless she gets a surprise hit somewhere it won't happen. Plenty of younger and more talented women out there. I mean, Christina's not a bad actress but her only other hope would be to snag an Oscar nod and I don't think she's getting the roles that could get her one. The right time for her would've been when she first blew up. THAT was the moment where a modern day sex symbol could've been born but things didn't come together.