There's a link missing in your reasoning. Can you identify it?
[Jeopardy! theme here]
Okay, so we go from "hey it's easy to make shovelware on the Wii and they'll do that as long as it works" -> "that will be the end of it." It will? O rly? How about they just incrementally move their production values up at the time (assuming it ever comes) when the channel gets saturated and people get sick of the "shovelware" (this is assuming these games are bad; I think it's more a question of the games not being to the taste of longtime gamers and couch potatoes).
Anyway, the point is that as long as people are happy buying the stuff, and it's not harming their health, I don't mind. But I don't see that developers are suddenly going to abandon the Wii with its lowered production costs for the huge consoles just because expectations are raised a wee bit.
Dang son, get ahold on yourself.
The Wii doesn't have better graphics because Nintendo execs made a conscious cost decision. Has nothing to do with the control system - the control system could exist and perform just as well (better actually) on the other consoles. Also, if you put together a GameCube and a Powerglove you still don't have motion sensing nunchaku, now do ya.