However much I might wish otherwise (because federalism is bad and anti-small-d-democratic), the 10th amendment explicitly gives all remaining/non-prohibited powers to States and not to the US. I kind of feel that makes them more canonical as a matter of law, even if that's not how we typically experience policy.
I can see no reasonable definition of “canonical” for which that is relevant to the claim that the states are “the canonical governmental unit” in the U.S.
If you mean “responsible for functions not specifically assigned by the Constitution”, sure, but that's not what “canonical” means, and in any case the regulation at issue is arguably squarely within the scope of the Commerce Clause authority, so it would be a dubiously relevant claim even if canonical meant that.
I wasn't arguing anything about whether this regulation at issue is within the scope of the Commerce Clause, if you read my prior comment carefully.