My predictions:
Rihanna seems to be trying to build a brand around her name but I am not sure how that will end up.
I think she can become a touring force if she works on her craft.
Katy seems to be doing ok. Her future is uncertain to me and her recent singles (uncle and Birthday) under performing show that people might already be tired of her. She's not really a touring artist either so....
Gaga needs a image overhaul if she wants to continue to be a major popgirl. Simple as that.
Britney is done. From Britney Jean onward she will continue to decline. Her expiration date has been long overdue. I think this will be a good decade for her because she no longer will make music a top priority. She might tour after Vegas but I dont expect to see anything groundbreaking from Briney.
Miley- Dont know honestly. I think the VMA performance was a horrible move from her though.
Shakira- Touring. Touring. Touring. Spanish Shakira= Relevant Shakira. FIFA
Adele- Might end up like Norah Jones OR could become an Icon.
Mariah- Go to Vegas. PLEASE!! Its time.
Taylor- If she decides to go full pop. She will flop into oblivion.
Jlo- A.K.A should be her last album for various reasons. She should focus on acting or go to Vegas.
She can tour if the demand is there.
Beyonce, Pink, and JT. will last they have become pop legends. They are touring monsters and they move albums. Their dedicated fan bases will grow with them into the future.