I think Adele will be higher - #2. Katy will still be top 3 and Taylor will be #1.
Britney and Gaga might make the top ten, thanks to FF, Scream and Shout, TFM, BTW, etc. Gaga might even make T5 if she's lucky, to be honest - pretty much the whole Fame Monster era counts toward this chart decade because it came out so late in 2009.
Bey & P!nk have a shot at T5 over Rihanna and Miley, tbh, but that all depends.