They do? I was under the impression that TPM was specifically designed to be able to be re-keyed, with the only permanent keys being "endorsement keys" used to verify the TPM's origin and identity (e.g. that someone didn't sneak in and steal your TPM or replace it with an attacker-controlled facsimile).

I am fairly sure you are incorrect.

But TPM information and documentation are unfortunately almost always behind a NDA. It makes pointing to definitive information difficult.