Don't know about anyone else, but I think that if a company announced that their console didn't play used games, Gamestop would refuse to carry it or carry much less.
They're the largest retailer of both new and used games. A lot of their profit comes from the latter. I'd imagine they have quite a lot of power over companies simply by choosing not to carry certain things.
Wal-Mart, Toys R Us, Best Buy, K-Mart and many other stores now sell used games, because it is pure profit for them.
I don't know how they'll manage to convince these stores it's worth stocking their product when they break a source of income these stores have been relying on for a very long time.