The new 1Gx was on sale only a week or so after the release, so they must have had stocks all ready to go, and I'm sure there are thousands of new 5D3's just about ready to ship too, if they aren't on a boat already.
I'm not saying that you are wrong, but do you know how long it takes for a company like Canon to bring out a new model like the 5D3?
It would take them at least 12 months just to put new sensor in it, let alone such a complete re-vamp as the 5D3 is over the 5D2.
First they have to have meetings about what they are going to do abou tthe new model, then hand make prototypes and test them, as well as the software and firmware testing - which takes ages on its own, then there is the final design so they can fit all the components into the camera, then the tooling.
Do you know how long it takes to make just the tooling to cast the body and then test it?
Then there is the packaging, the pricing structure the advertising and marketing materials - the list is endless!
They aren't just making sausages, but very complex pieces of mechanical and electronic equipment!
I reckon the 22mp in the 5D3 is more than enough to get really good photos, and is better for high ISO than 38mp.