The main problem as I see it is that Canon don't really have any real development momentum (or budget!) on higher resolution processes. They outsource almost everything except for the larger format sensors.
The biggest difference between the others and Canon is that all the other manufacturers are all dominated
by their small-sensor image sensors sales, that already now are manufactured at 90 and 110-130nm metal processes on 300mm wafers. Panasonic and TSMC will start volume shipping of sensors made on 65/45nm rules in Q1 2013. Lower mask resolutions than 130nm are not enough to land you any sales any more. Most cellphone and compact camera sensors are manufactured at those levels now, and have been for the last few years. Also consider the fact that some of the others have very large yearly revenues from logic CMOS processes at 45, 32 and even 22nm levels. All of those markets are areas where Canon totally lack any type of experience. Canon outsource all more advanced fabs on their camera bill-of-materials.
The Digic sensors are made by UMC http://www.umc.com/english/class_300/index.asp
, and were designed by Texas Instruments http://www.ti.com/lsds/ti/apps/videovision/end_equipment.page
The memory is most often made by Samsung http://www.samsung.com/global/business/semiconductor/product/consumer-dram/overview
The memory/Digic package-on-package mount has to be outsourced, since Canon cannot do it themselves, and it is believed that UMC does the mounting too.
Other peripheral control and logic chips are TI, Mitsubishi, AD and Fairchild.
Going from a 500nm process to 180nm is like going from a 10MP FF camera to a 70MP camera in one generation
. This means some really noticeable strains on the process, especially since the CMOS manufacturing process isn't as forgiving as just "taking pictures". You cant "scale to web size" and sharpen in post when you're making CIS wafers.
What you're basically asking from your equipment is to all of a sudden provide compact camera type linear resolution in a FF lens projection coverage - something almost unthinkable in the normal photographic world. The process has to be precise, to a degree where every single contrast and item on the new 70MP image is equal to or better than the 10MP camera - per pixel
. In normal photographic resolution usage, we just want the final output to be good enough, which means that we downsample most images - we seldom deliver full-res images to the customers, and we seldom use full-res images in our own output.
Going from a 350nm mask to 250 and then 180nm and 12" wafers was a BIG step for most CMOS manufacturers, and most other manufacturers are a LOT bigger than Canon in this area.
............So it's not that Canon COULDN'T do it
. Even really small (in the imaging field) firms like STMicro can do it by stitching, and thereby tripling the unit prices. For Leica this isn't really a problem since the total BoM on a M series camera is most certainly lower than 2k USD. This gives a healthy margin up to the projected 7k USD end price point.
This isn't what Canon does. They live on volume, not on extreme margins.