Interesting point you raise there.
Do you think that Apple would have preferred to keep the upgradability to a minimum just like with the iMac but manufacturing necessities outweighed their original intent?
If this was the case they could have gone with proprietary everything including sockets and connections to achieve the same goal, right?
I am still wondering what's going to happen to the next Intel CPU socket, will it be compatible with this generation of MacPros?
Like I said before, interesting theory you got there.
I don't think Apple
prefers to keep upgradability to a minimum. That happens to be a natural outgrowth of the design goals for their consumer product lines. The vast majority of consumers do not need to pay for card slots and easy access to drive bays. They do want reliability and affordability, and nearly anything you do to enhance upgradability reduces reliability and increases cost.
The goals for the Mac Pro are somewhat different - different end users with different needs, different manufacturing quantities, different budgets. Hence, a different solution.
Why wouldn't Apple use "proprietary everything?" You only reinvent the wheel when you need to. Custom circuit boards to fit a particular enclosure, standard components on those circuit boards.
The design goals for the Mac Pro precluded the use of off-the-shelf graphics cards - they wanted high-efficiency cooling, they wanted compactness, they wanted to integrate two GPUs into the fundamental design. Effectively, these are not graphics cards at all. If this thing had a motherboard/daughterboard configuration, you could think of them as two out of three motherboards, one big chip per board. There's nothing at all weird about taking a component that's integral to a design and moving it from an after-market card to the/a main circuit board. I remember when you needed an after-market audio card, an after-market i/o port card, a VGA graphics card... those functions moved to after-market multi-purpose cards, then to the motherboard, and after that, right onto the CPU die. And so it goes.
The next Intel socket will, by definition, be incompatible. It's been that way since the beginning. If you add more functions and capabilities, you just may need more pins. Down the road, it's likely you'll see the entire Mac Pro configuration on a single chip - multiple GPGPUs plus multi-core CPUs. That will almost definitely require a different connector.
It's not a conspiracy on Apple's part. It's rational engineering analysis and design. Look at their products, look at who buys them, how they use them, the cost of manufacture, the built-in cost of warranty repair, the competitive landscape, consumer appeal (sexiness)... it's easy to find quite rational, unemotional reasons for everything they do. No malevolent intent is necessary. But of course, if we all thought like Vulcans, these forums would be really boring.