Not surprising. If Microsoft announced that the next release of Windows would require that the motherboard be coated in laminated chicken fat, there would be a run on chicken fat.
In this case, I suspect MS may have to back off the absolute requirement for TPM, at least for the initial release. If so they'll just add it back in later, after people have a chance to get used to the idea.
I'm not a fan of TPM, it looks to me too much like a design-by-committee with everything including the kitchen sink thrown in to please somebody. It's fairly complex, and that leads to insecurities that will be hard to address in the hardware implementation. Who would want to download a firmware update for their TPM? Will it brick the machine? And whom do you trust?