Yes, it does work that way.
There have been many processors connected together that, when working together become supercomputers. The Scorpion may not be designed to be strung together to get to supercomputing power, but the processors can be divorced from the platform and put into different platforms to create a much more powerful computer.
The Xeon configuration that Apple uses is not exclusive to Apple, and any OEM can do the same, and perhaps a lot less expensively. But, there has not been a big need for such computers in the small business space or in the regular consumer environments; what Apple is simply doing, is trying to regain the WOW factor that they lost some years back, but that iMac is not going to get it done for Apple, since what the Macs used to be used for, can now be done with PCs at much lower costs and without the stupid wow factor.
Apple needs to move on and forget about their deception with the iMac.
BTW, by the time that Apple releases that computer to market, others may have copied the configuration and at much lower costs. That iMac is not scheduled to be out until some time next year, and perhaps never. It remain, for now, a talking point and smoke. And since it’s way too expensive, even for the target audience, Apple may be forced to drop the whole idea.
I know about cluster computing, but it is not so easy as you claim. As I said, the company that makes your "gaming" speed demon also makes workstation computers with Xeon processors. I just configures one with an 8 core Xeon to closely match the iMac Pro. . . Here it is. It comes in at $5,472.00 with an OLDER, FAR SLOWER XEON at 2.1 GHz than the 3.2GHz Xeon Apple is putting in their $4995 iMac Pro, slower EDD RAM at 2133 GHz than the 2666 GHz that Apple is equipping their iMac Pro with, and NO 5K MONITOR at all, in fact no monitor at all is included at that price. . So much for your less expensive claims. You don't have a clue what you are blithering about. Not a clue.
Keep dancing. You don't do it well.