It's silly to think that TP's sales weren't affected at all by being a launch title on what was an extremely popular console in 2006-2009. I guess Super Paper Mario sold much better than the other games because hardcore fans really loved the type of game SPM was ( they didn't, lol), and it had nothing to do with it coming out a few months later after the Wii's launch.
---Member of the official Squeezol Fanclub---