Because after the game has been released and we've played the bejesus out of it, the MK team could easily conjour up some sort of expansion disc to go with MK6 with some new charecters and some new arenas as well.

I dunno if the MK team is too far in to make it or not, but if they could make it so that charecter models and skins were easily messed with on the PC, like make the model file-type compatible with 3D Studio Max or something and move lists easily edit-able(?) the MK community (those of us with MOD chips or something) could trade versions of MK6 with charecters we would have liked to see, but weren't put in.