-Rihanna and Britney will both make it past 10 considering they're both more than halfway there already...
-Taylor and Carrie will both make it considering they're both preparing their fourth albums, and country artists tend to have more longevity than pop artists... although I'm positive both will follow Faith Hill's path of taking a decade or so to raise their children before making a comeback.
-Gaga, Beyonce and Adele will all continue on to release up through their 10th albums.
It doesn't really matter if an artist makes it to 10 albums though... Shania Twain is only working on her fifth album, and she's already legandary.
