We didn't get rid of all of our shit/disinterested players on ridiculous wages mind mate, a few aye - Owen, Viduka (both out of contract), Beye, Duff, Martins, Bassong were the main ones we moved on. Kept paying players like Smith, Xisco and Butt until their contracts were up years later.
In reality the main reason we went straight back up is that we managed to keep a core of capable players at the club (probably out of sheer good fortune, as we seemed to be going for a fire sale and there seemed no takers) - a few more exits from the likes of Coloccini, Jonas, Nolan, Barton, Enrique and Carroll and we'd have been fucked.