At the height of popularity, Eminem went AWOL for five years due to personal and drug problems. Don't count him out-his Relapse was one of the best-selling albums of 2009.
I think Eminem's popularity dwindled in previous years because he wasn't putting out anything new and when he did it wasn't up to par with what people knew Eminem could do. I think with his latest album he's back on top again.