This is how federalism works. The federal government could step in and force all states to do something, but in many cases allows the states to self-govern.
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
To borrow Money on the credit of the United States;
To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes; ...
I read right over the words you wrote because I'm so used to the phrase interstate commerce and not at all used to seeing intrastate commerce. I wasn't trying to use Article I to argue that the federal government had any right to regulate INTRAstate commerce. Sorry about the mixup.
So, now your original point makes much more sense, and I completely agree with you. Thanks for taking the time to reply.
(The federal government can't force all states to do something because 1. the federal government's force is limited by its powers, and 2. the states together have powers to overrule the federal government)