Anyone is a Global Superstar and gaining fame points?

Once you are a global superstar, you're at the top of the fame ladder...I don't think you get more points to spend at that point. Fame Points, which you spend, are not the same as Fame that you earn by doing things.

Earning Fame adds to the progress of the crescent shaped meter on the right side of the Public Image section of your simology panel. You get Fame Points, to spend, when you fill the gold stars along this meter. Once you are a Global Superstar, you have ALL of the golden stars filled, so it just makes sense you aren't going to get any more fame points. You do still need to keep earning fame though, or you will lose your superstar status.

"Parvati;c-16915489" wrote:
so why then are there 21 fame items available if you can't have more than 10? and where are these great movies I'm supposed to get on? :P

You can always do a Celebrity Cleanse. Then you can purchase different perks.

Also, be wary. My Sim is a Global Superstar and he got a notice recently that his star was dimming and he would lose one, if he didn't so something about it! So, while you don't gain more points, you most certainly can lose them if you don't constantly maintain your Sims' status. IE do those interactions with the Fame + next to them, mingle with fans, sign autographs, do Selfies, update your Simstagram and check on the online stuff. I have worked my newlywed, new Dad star's hind quarters off just yesterday in my game, trying to prevent any slippage. Balancing private life and public life can be a hassle, but he's also fond of eating, too.

Also, I believe the quirks that come along are random. Some may be interaction based, not sure about the rest. As @dizzydee_k said, there's always the celebrity cleanse.

Yes, there is a maximum of 11 points. After you've gotten 11 there are no more unless you decide to cheat for them.

Fame points are gained when your sim gains a fame level. First star gives 1 point, fifth star gives 3 points, all the others give 2 points. The max amount of the points is 10 fame points. However, if you complete the World Famous Celebrity aspiration, you'll get one extra point (giving you the 11th point).
If you want more than that, cheat. The cheat is this:

famepoints 

so why then are there 21 fame items available if you can't have more than 10? and where are these great movies I'm supposed to get on? :P

You have to choose your perks -- that way you can take a different patch with a different Sim so it's more replayable.