If they don’t then the devices are not sold in the United States. It’s quite simple.

Great to know that smuggling hardware into the US has been completely stopped.

If the analysis above is accurate, a few smuggled devices would not be an issue, as long as the zillions of devices sold at Walmart are compliant.

Congratulations on the creation of a thriving new black market in which the main beneficiary is organized crime! What could go wrong?

Do you take issue with the concept of laws or are you just being annoying?

I'm sorry that you find thinking about second order dynamics annoying, but that's what you have to do if you actually want effective laws. Just making laws doesn't magically fix problems. In many cases it just makes much more exciting problems.

I'm annoyed because you didn't actually come up with an interesting response. Yes, when you make laws people can break them. But you need to explain why there is an incentive to break them, and whether it will happen to the extent that it will actually be a problem to enforce. Personally, I don't see people scrambling to get DDoS attack vectors in their house by any means necessary.