The 6d is an introduction to full frame for enthusiasts. people with a simple rebel who like portrait and landscapes can get simple features. You get good iso performance and full frame. You shouldn't need fast shutter speed or "the best focusing if you are going full frame. If so, you should go for a 1dx or 5d iii. It also gives them a chance to try wifi and gps without spending the money. This will get people buying either the 7d or the 6d. Then they will upgrade to the 5d iii or the 1dx, or the new 3d at a later time. Then they will by the wifi or gps accessories.
But, canon is pulling the wool over everyone's eyes on this one. When the "3d" comes out, pros will replace the 5d iii with that, and use the 1dx for speed there will be a lot of cheap well maintained used 5d iii is and the price will drop. Everyone with the 6d will try and upgrade. The 6d will be worth less, and amateurs with a rebel will get the 6d, so even if no one buys this now, it will sell eventually. Canon wants to have everyone jump up on full frame, and then spend money on the gps unit, wifi unit, and more l glass.
So in the final analysis, you could get screwed if you buy this, but if you're an enthusiast who wants full frame, is trying to start their own buissiness, or wants to see if this is the industry they want to try and become a pro in, this isn't such a bad camera. Plus, you could always buy a 1d mark ii, mark iii, or 50d to get the speed and focusing.