The interstate highway system was considered to be allowed under the power to legislate for national defense. AI development doesn't seem to be less relevant to defense than roads.
For example, states can allow people to drink under age 21, on the interstate highways they own.
But the Feds can refuse to pay for the highways if they do.
Seems much less relevant to me but maybe my thinking is too small minded (probably because I don't believe LLMs are a path to AGI).