You don't verify the hardware directly. You provide a mechanism for client certificate validation (I issue the certs, I can assert that they're tied to hardware

You don't verify the hardware directly. You provide a mechanism for client certificate validation (I issue the certs, I can assert that they're tied to hardware), and you provide a callback for validating device state (I define the validation policy, I compare that against the data that I have and say yes or no). It's not about services taking responsibility for this themselves, it's about providing mechanisms for customers to have their own policies enforced.