All except Kesha, Kelly Clarkson, Shakira and Leona
Katy Perry - for some reason the US love her so she'll be around for at least another 8-10 years...
Lady Gaga - As much as I love her, I think people might get tired of her by around 2016 so maybe if she takes a break for a while and makes a big comeback around 2019/2020.
Britney - I dont think Britney will ever stop tbh lol if shaving her head and having a public breakdown doesnt do it, I dont know what will.
Pink - She might go on a break for a few years as shes got a baby now but im 100% sure she will make a comeback sometime around 2014/2015.
Adele - Only just achieved huge success so shes not going anywhere ..
J-Lo - Im sure she'll find someway to re-brand herself and release a new album off of the back of it.
Christina - She'll never be as big as she used to be, but as she went on a break a couple of years ago, she'll do a J-Lo comeback, from diva to settled down housewife sort of thing.
Avril - Probably release more fail albums untill she gets hit by a bus or something..
Rhianna - Shes never going to leave
Beyonce - Might take a break to be a mum for a few years but comeback when shes shed the baby weight. (or re-brand herself as Momma B or something)
Nicki - Shes quite new so will stick around for awhile