I'm not sure what you're disagreeing with? Your point and mine are the same as far as I can tell. The 1 series bodies are built for high volume work. High volume cameras tend to be speced with lower megapixels and higher framerates.
I am really hoping they opt for the 5D series body. I think that would make more sense because the 1D series cameras are built for people who shoot high volume work. High megapixel shooters tend to do low more low volume work.
Plus, for all the 5DII users who didn't upgrade to a 5DIII because of a lack of megapixel or IQ improvements, a higher megapixel 5Dx would finally give them a reason to buy a new Canon camera.
...not always. I shoot high volume at times - and I love my 1 series body. I despise the 5-series because of how small the body is - it hurts to shoot for hours on end with it!
My point is that a high megapixel sensor is not really going to be benficial to high volume shooters in most cases (and some might even consider it a detriment because the larger file sizes slow down a high volume workflow.) So why put a high megapixel sensor into a 1 series body that is built for high volume work?
Hmmm, I use my 1D for high volume, but my 1Ds for low volume, high-res work. The 1 series isn't about speed always - it's about reliability, familiarity, and guaranteed output. I may only shoot a total of 200 frames for a wedding, 20 frames for a product shoot, and 1 frame for reproduction work. That's not very high volume, but does require the *resolution*. I can also share all my accessories that between 1D / 1Ds lines. 10fps with tubes on? Done that shooting macro. 1 shot with a 400 on, done that too.
But wait, I've shot a dance session that was over 2000 frames with the 1Ds. That's pretty high volume and high resolution.
I'm thinking that you actually don't own / have never owned a 1-series body. Holding a 1Ds all day is a lot better than holding a 5-series all day. When it rains during a shoot, I don't stop and put rain covers on, I keep shooting - and at very low volume, 21mp rates. I've dropped my rig in mud, sand, water while shooting landscapes. I've laid my camera in puddles to do low level shots. And, I never worried about the camera once.
I guess you think that ultra high-res Hasselblad shooters also do low volume work - tell that to the shooters who routinely shoot 1500 shots in studio on a daily basis doing fashion/catalog/modelling at 50mp.
The money is in consumer cameras where they'll sell a new model everytime one comes out to the same person - because it has new features and gimicks. That new technology trickles up slowly to the top of the line through the Rebel->xxD->xD->1-series. Most 1 series shooters don't care about the newest, latest/greatest. We want something that works, is tested, stable, reliable and gets our goal done without having to think, worry, or fiddle around. The camera is expected to produce repeatable, consistent response as soon as it's picked up - and for years to come in any condition and no matter if that is 100 or 100,000 frames this week.
I agree the 1 series is about high volume work and reliability, easier and more comfortable to work with for daylong handheld shooting. I agree totally and completely. I don't understand where you think I've said something to the contrary?
Yes, I know that some MF shooters will shoot a thousand shots a day. I also know such shooters make up a relatively small portion of the market. When I say "high volume" I am typically refering to photojournalists, sports photogs, high end wedding shooters...people who generally will take speed and reliability over megapixel count.
But at the risk of getting hung up on semantics: 21mp is not really "high megapixel" anymore.
I've got a friend who is a high end wedding photographer. He's shot Nikon forever...he picked up a D800 and tried it out for a wedding. Loved the images but hated the big files and slower workflow. The benefits of a high res sensor might be noticeable in a fine art print...but not to his wedding clients. He gained no upside from the bigger sensor.
The point is that in general photographers who as a practical matter want more than 18-21 megapixels are more likely to be shooting low volume work. This being an internet forum I of course must explicitly spell out the disclaimer: not ALL cases...in GENERAL. We're talking in broad brush strokes here. Landscape photography, architecture photography, fine art, etc. These are the types of shooters who most frequently want more than 21mp. These are also the types of shooters who benefit less from the more robustly performing 1 series bodies.
(Nikon already has recognized this logic which is why their top performing, highest priced flagship camera is not their highest megapixel camera.)