OK; each motherboard has a BIOS chipset (firmware - software on hardware with some part upgradable via flashing the bios) but, NO you can not put just any processor on any motherboard (think speed - if the motherboard is designed for certain speeds it won't go faster, nor a wider / 64 bit processor in a 32 bit bios / chipset; etc.) Memory has different types and different speeds, etc.
I respectfully disagree...
We're not talking about ANY processors. We're talking about digics - specialized mainly signal (image handling) processors of one manufacturer, based on special purposes design. They Know their design. If "30 years" you Know that chipset has nothing to do with it. You can have chipset with bios working with any processor, as far as io, memory and bus are properly operated and based on same microinstructions (yes, I programmed in assembler, also embedded devices). This is not about putting any processor. This is about design allowing inserting a next generation processor operating in the same environment. It's not about design allowing put 128 bit processor
in 64 bit address space (let's look forward) without compability handling.
It's all about making everyone happy. Please archangerichard don't try to say it is not possible to design an architecture where just one or just two digics must operate at a time. Is it really not possible to give people a choice - you have one processor in standard, you want two (to have 10 instead 6 fps) - pay 200$ (300, 400...) more?
Is it really not possible to design microadjustment allowing to position a sensor properly? Is it not possible to design some simple lens-like ef mounted cap with some holes or led/laser assisted sensor positioning?
What differs digic2, 3, 4 and 5 in terms of board circuit design?
Can digic 4 or 5 (ie) work in different camera łines like powershot and eos with no respect to the sensor they operate on?
I think techs are not really so important - a Man was sent to the Moon, a Man could design cheap interchengeable sensors in a camera.
Maybe time didn't come yet? Maybe in 3 years? But why not now? Look how very different expectations from 5d3 there are. Some want high iso, some MPs, some don't bother about lazy AF.
The question is: how you maintain all these (sometimes) opposite requirements without forcing people to buy 2, 3 or 4 different cameras for their purposes and without canibalizing the flagship model? Could the winner in this slr battle be the player who offers this as the first one?