That's not part of the threat model - the encrypted data is lost, the point of the defences are to prevent damage to things accessible from that specific machine, not to prevent stealing the machine.
That's not part of Microsoft's threat model. Which is exactly the problem! It could be done, if only Microsoft supported that use case. But with an open source bootloader, we could make the necessary changes ourselves.
No, that's the threat model that most clients that require high security have (the machine is often nigh-infinitely cheaper than the data and access rights), and MS, surprise, explicitly insists (in difference to secure boot spec) that owner of the physical machine is, well, it's owner and can reinstall, resell, etc.
I don't see how any of this is relevant. All I said was that it's an interesting possibility which has now been made feasible. Who cares about the threat model that most high security clients have? If they don't want it then I'm not talking about those clients.
Besides: the prevalence of terrible software like Lojack/CompuTrace in the enterprise just goes to show that many clients actually do care about physical theft scenarios. Also consider how basically every modern mobile device now provides factory reset protection.