That could be done with an executive order in the US, and it probably wouldn't take much to get it to pass congress.
Now, don't worry, businesses can still buy a lot more GPU compute than that, but they have to register and track their usage just like any other company making/buying weapons.
"Must declare any purchase of 10 or more GPUs" does not strike me as particularly implausible.
There's already plenty of jurisdictions where possession of certain tools is considered evidence of criminal intent.
I don't think any of this is good behavior on the part of our legal system, but I do not doubt the legal system's ability to regulate this if it so chooses - and Anthropic has already gotten slapped down by the Trump administration once before.
Works very well.