It sounds like what happened to Jenny Dell at CBS in terms of her career track. It had nothing to do with age for Dell, I think the powers that be just figured out she sucks.
Her first year at CBS, she was on the sidelines for the NFL. That is the most prestigious job, and the only way it could get *more* prestigious was to work her way up to the #1 broadcast team.
This season, AFAIK, she has disappeared from the NFL. I saw her earlier this year doing a Friday Night CBS Sports Network college football game. I was something like Utah State against Boise State or some other meaningless matchup like that.