Fully agreed on attested bootchains. General-purpose level OS-wide attestation is indeed a blight on open computing: It's ineffective because it implies a gigantic trusted code base (what are the odds that the entire Windows kernel is completely free of vulnerabilities?), and conversely it does tie you to somebody else's more or less arbitrary kernel build.

Almost complete disagree on TPMs. A better comparison than a spy would probably be a consulate (ok, maybe an idealized one, located underground in a Faraday cage): Their staff doesn't get to spy on you, but if you ever do want to do business with companies in that country and need some letters notarized/certified, walking into their consulate in your capital sure beats sending trustworthy couriers around the world every single time.

To torture that analogy some more: Sure, the guest country could try to extend the consulate into a spy base if you're not careful, and some suspicion is very well warranted, but that possibility is not intrinsic to its function, only to its implementation.