Many of users here are wedding or other small photography business owners ( easy to understand why) but success of the 5D in my mind was due to all advanced amateurs on steroids of Flickr like sites and instant "fame" coming out of it, brave enough to invest $2500 in the new camera body.
If Canon is listening only to this type of forums it may just miss the real target, with its cheated high ISO JPEG performance.
Constant rising prices, especially being greedy in basic features, (trust me, they will soon appear in other product for huge premium that Canon is making space for) may be short sighted, and next 5D can end up as just another elitist toy in the hands of professionals only.
I am very advanced amateur with gallery exhibitions in the past and able to function as professional in pretty broad range of photography.
For me plan for the next 5D was to only use for landscape photography with super wide angle lens, no system required at all, and just like my daily landscape walk around Rebel will be replaced with Nex 7 camera as soon as super wide lens will be available, 5D can be replaced as easy for anything else that is more appealing.
For every other needs with other lenses in my cabinet there will always be something like 7D (I hope)
Anyway, I am in a niche of course but, I have spent many thousands of dollars in the past with Canon! One would wonder if we in the small niches are important enough for business.
Something tells me that we better be important, because in the end every single photographer represents some very particular small niche, and all those single lost niches can and will add up in to something potentially serious.
Even if it's a let down, i would say canon still have its advantages from their lens system. Try and compare with Nikon lenses, you will find that varities is low and the pricing it much higher. I guess if the spec od the new 5Dx is lower as compared to D800, you may also find it hard to switch if you look at the whole big picture.
Agree that canon still has a few more unique lenses. None I consider essential for me though. I think Nikon's system is well stocked, and more importantly, continue to fill in gaps specially before the thai flood wrecked everybody's roadmap. Newer canon lenses such as the 24-70 and 70-200 have all been more expensive than their nikon twins. For me, they got all I'd need and a few lenses I wish I had in canon version so I don't feel held back at all by their lineup. The real reason I don't switch is because of the hassle and because I don't honestly care for what brand I advertise for free on my camera gear