This is the actual missing key bit. The problem that Google is trying to solve here is not actually a hardware / computational problem, it's a Real Identity problem. Hardware / TPMs are a poor proxy for solving that problem.
There's drastically less eWaste and impact on software freedom if you seek attestation from a national ID provider than if you seek attestation from one of a handful of personal electronics OEMs. National ID providers can offer to sign not only Real Identity attestations, but also anonymized attestations to protect citizen privacy. A web operator can decide whether to allow for attestations from only their own national ID provider, foreign national ID providers, private ID providers, or none at all if they just have a read-only site and don't really care.
The truth is that government inaction is forcing Big Tech down the road of violating user privacy and freedoms to solve Big Tech's problems. But getting the government to offer a flat Identity Provider playing field would solve these problems in a way that doesn't require such violation.