They also won government contracts by not doing it; the High Assurance Platform mode (‘setting the HAP bit’) was a feature implemented by Intel for the NSA, incidentally discovered by security researchers.

Dell sold laptops with this as an option until they were asked not to.

It would be pretty easy for a sizable country or even a wealthy US state to demand that these ‘secure’ co-processors can be disabled at the user’s discretion, via regulation.

From the NSA’s perspective, having the keys to the backdoor is an asset, but having a backdoor at all is a huge liability, now they’re not the only game in town. US businesses and citizens simply have more to lose.

Honestly, I think it’s laziness and inertia more than conspiracy.