Re: The mind absolutely boggles.
"486SX, 487 CoPro and 486DX being a case in point"
As with many things, the seeming "deliberate disabling of parts of the chip" wasn't actually the case and it was actually a case of extreme binning.
Yes, sections of the CPU were disabled, but the reason they were disabled is that they FAILED testing - disabling the CoPro enabled Intel to sell a CPU which in other circumstances would have been a dead loss. Once yields rose to "better" values 486sx CPUs became a very rare beast indeed - because there's no added value in zapping a perfectly functional copro and selling the results at a knockdown price.
AMD are doing exactly the same thing now with their various RyZEN CPUs. Those lower-end chips with disabled CPUs onboard are sold that way because not all the CPUs passed testing.
The ME's existence and functionality has been documented for years - what's NOT documented is that it's there on the non vPRO chipsets too (just disabled - supposedly). Because the code and internals have always been a secret, we've always been a little suspicious of the things - to the point where we watch for network activity on the ports it uses.