Not sure where you are getting that. For starters, wouldn't it be two attractions closing (Backlot Tour and LMA)? Second, I'm under the impression that the current plans have 2 rides for Cars Land -- the Mater ride and a fully indoor version of RSR (though we don't really know the specifics). Finally, even though no one has suggested other rides, it's quite possible/reasonable that other Pixar themed rides could come to the area, especially Monsters Inc given the nice opening weekend they just had and since there has been previous plans for one.