Canon might regret introducing the EF-S concept only if/when they lose large numbers of 60D sales because consumers realize that can upgrade to a Nikon D600 for about the same cost as upgrading to a 60D and they buy the Nikon instead. In contrast, a Nikon D200 user, like a nephew of mine, can purchase a D600 body only for now, can use his current lenses and can buy more lenses as finances allow. As for why he would want to "cripple" his new camera with old lenses, consider that his wife is 7 months pregnant with their first child. A D600 body alone will be financial stretch.
And that is my point. If he spends $2100, he gets a camera that downsizes all his photos to the same 10-11MP range as his current D200. What has he gained for $2100 with his crop lenses? Not much -- he's effectively throwing out half his sensor that he paid so much for. He might be better off spending the $2100 on good glass, which would affect IQ a lot more, or combination of glass and a more capable crop body that he can take advantage NOW. If he can't get FF-compatible glass for a few years, then it really doesn't make sense to get a FF body now. Bodies are updated a lot more frequently than lenses.
That is not to say that if one buys a crop camera that you should ONLY buy crop lenses. The 17-55 has IS advantage over Canon's FF options and the 10-22 is much less expensive and nearly as capable as the 16-35. Focal length limited shooters also gain from the crop cameras' higher sensor density. I think it is also a reason why there are relatively few non-kit EF-S lenses. Most of them are kit lenses except for the 10-22, 15-85, 17-55 and the 60 macro. One is a ultrawide that is needed for the smaller sensor, and two of them are mid-range zooms which is what most people use (not sure why Canon developed the 60 macro). If you want a Canon high speed prime or longer focal lengths, you'd be getting EF lenses anyway, which can be used on FF. With 1 to 2 to sell/trade, the cost of moving FF is not that high.