Making this about Pluton rather than about TPMs in general just means that people will believe they're somehow safe from the worst case outcome because they bought a CPU that doesn't have Pluton
They certainly will be, if most people don't have Pluton. If only a minority have it, they wouldn't be able to even come close to requiring it.
Windows has had TPM 2.0 since 2016, and remote attestation can be accomplished with the TPM only without Pluton being necessary. However, Pluton has its own issues and appears to make implementing attestations easier, by supporting different attestation protocols - and by potentially receiving new updates for that functionality later on. Pluton is also significantly stronger against attacks which have occurred on TPMs previously.
Windows 11 requires hardware that enables this capability. Any Windows certified client systems have required this since 2014. Pluton provides no attestation capabilities that are not present in TPMs.
They certainly will be, if most people don't have Pluton. If only a minority have it, they wouldn't be able to even come close to requiring it.