Depends on how much "nothing" is. Eminem's last album sold 700-800k so I think it is safe to say that D12 will sell 100k or something like that.
Cashis' album will sell nothing, I agree. I reckon it is only a matter of time before they get rid of him anyway.
Slaughterhouse and Yelawolf will probably sell about 40-60k each which is still very good. Talib Kweli's new album (independent) sold 14k first week in the US but he is touring everywhere in the world and making a lot of money.
As long as they don't spend more money than they make, it should all be good.
I don't think age matters that much anymore. It has only ever been an issue because hip hop is a "new" genre.