I don't even like Earthbound, but saying Ness is a has-been is pretty stupid. Honestly, if you're playable in Smash Bros. (or even an AT for a matter), you're pretty much guaranteed to not be a has-been. Sure, Ness only had his one game, but it's got such a massive cult following that calling him a has-been is crazy.
Has-beens are guys like Gex or Bubsy.