Yes, but the point is that the Canon system is designed around the EF mount. If you have a 7D, you have the option of shooting only EF glass, if you want. The EF mount predates EF-S by 15 years.
The situation with Fuji is exactly the opposite. The XF mount cannot be shared with a FF camera, and thus all of Fuji's existing lenses become useless for those of us who would be in the market for the FF camera. Fuji would be forced to bring out a second set of lenses, which could ONLY be used on the FF camera, in the absence of an adapter.
For the Canon EOS shooter, all of the EF lenses bought from 1987 onward are compatible with the 1DX or 5D3. So the investment in the system is intact. But if Fuji brings out a FF camera, it essentially becomes a totally new camera system, because I *know* my XF 35 f/1.4 isn't going to work on that camera; the mount just isn't compatible, and the image circle is too small. Perhaps the FF lenses could work on the APS-C cameras, which would be great, but what about those of us with investment in XF glass?