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The reason why a lot of folks were (and still are) so frustrated with the pricing and think it represents a poor value is that if you start with the configuration you want, and that doesn't happen to align with the available configurations on the Mac Pro, then it can feel like a poor value. And it's further frustrating because the MP is the only choice in Apple's lineup if you want a stand alone desktop computer with more than an iGPU and a CPU/GPU that can run full throttle 24x7.
Let's say I have a choice between getting a PC or Mac workstation, and I determine the best hardware specs for my usage would be:
Xeon E3-1271 v3 (quad 3.5-4GHz); single Quadro K2200 GPU; 16GB RAM; 500GB SSD
This is pragmatically far more a desire for a different product than a different configuration. Built in here is a presumption that there is a general box that stuff different motherboards into to crank out a number of product variations with lower container changes.
The better "I want an xMac" value in the Mac ecosystem has historically in the 2nd Jobs era largely been the "Mac Pro" 1-2 models back. Given the shift in the targeted market ( really desktop versus deskside ) and the 2 (or more ) year spacing gaps between upgrades that is breaking down.
More focused feedback to Apple about iMac "full throttle 24x7" failings will likely have more traction than getting Apple to do an xMac. It is doubtful Apple is going to be convinced to expand the desktop line up at this point. Where and what users are shifting to buying will drive what new Mac products they may/may not bring to market. Just pointing at the other classic PC vendors and saying "do what they are doing" is likely going to have very little influence. None of the major players there are doing better than Apple is doing Macs with the "make every product possible" approach. So I'm not sure why that would lead to frustration. You can ask them to get on a different path. Whether they "switch paths" depends upon the value they see, not the value you see.
The xMac has serious iMac fratricide problems. Folks hand wave those away as "Apple's problem" or as much smaller than they are. Apple sees it as their problem to solve and so they do... from their perspective.
Apple is even more a systems ( hardware + software ) company than there were. Their major value add is integrating all the "stuff". They aren't a contract design firm; "you pick the parts and we'll build it". Nor are they a "bare bones" vendor; sell me a starter kit and I'll add the rest with my trusty screwdriver. If Apple advertised themselves as being a contract firm then there would be a frustration disconnect. They don't. More than a few folks here spend time wishing Apple was a different company then they have been and are even more so now.