They mentioned number portability in the article, I guess Chili didn't have that before either? At least we have here. I do think if you own the phone, you should be able to use it with any carrier it's able to work with. With a subsidized contract price, that might not be for 2 years after activation, but then it should be yours to do with what you wish.
The analogy that comes to my mind is that of console specific video games. Game companies want to make the most money possible, and they can sell more of the same game on multiple consoles, 360/PS3/Wii, etc, than if a game is locked to one system. Epic makes Gears of War for the 360 cause Microsoft gave them gobs of money, but without that contract they would make their game for as many consoles as possible.
If you want me to buy your phone, make it kick-ass, then I'll go with the carrier that suits me best. I like the idea.