5) You can't have both an entry-level full frame camera and a flagship APS-C body. Setting aside the fact that this mysterious full frame camera has yet to surface, why can't you? If given a choice between a fully-equipped 7DII that basically mirrors the 5DIII in everything but sensor size vs. a stripped down full framer that causes all my telephoto lenses to lose more than a third of their reach, I know which I will pick. Both cameras can exist side by side because they both have different target markets.
Of course we know the differences between a flagship APS-C and an entry-level FF, but that's not the point. We're the 1% who follow this stuff every day. For the average consumer, they're going to walk into a Best Buy and have two options with vastly different feature sets for a similar price.
Can you imagine a 16 year old Best Buy rep trying to explain the differences between the two bodies at a store? It'd probably go something like this:Joe:
"These two bodies are basically the same price, what's the difference?"Best Buy kid
: "Well....ummm....hang on a sec. Wait! It says right here that this 6D
has 22 megapixels and this 7D mark II
only has 18 megapixels. So obviously the 6D is better."Joe:
"Oh cool! 22 megapixels sounds great! But what's this thing about 10 FPS on the 7D mark II
? What does FPS stand for?"Best Buy kid:
"Ummmm....hang on....I'm not seeing anything on the display about that, but I'm pretty sure it just means it's a little bit better at blocking out the sun than the other one."Joe:
"Well that won't be a problem because I always wear sunglasses."Best Buy kid:
"Well then it looks like the 22 megapixel one is the way to go!"Joe:
"Sounds good to me! Hang on a sec though, I'm going to put a picture of my new camera on Instagram."
In all seriousness though, I think you're right that they can co-exist, I just think it will be more difficult to do if Canon tries to squeeze three new bodies in between the T4i and the 5D mark III without stealing some of the 5D's thunder.