It is true that in this culture, they throw you out when you get older. I see it all the time, especially in my business. At my age, you're playing somebody's mother - and there aren't even a lot of those roles!
Britney Spears and Christina Aguilera are doing pretty well at getting noticed - a lot of people are doing pretty well at it. But you wonder whether they'll last, because many of them don't have the ability to get an audience to love them. You say, "That's a fabulous body" or "I like that song"; you don't say, "I love them because I know them." You can't know them.