Do you think the current (or future) US governments will apply the DMCA to these trillion dollar companies with the same gusto that they use it to, for example, push Aaron Schwartz into killing himself, or threatening teenagers with lifelong federal prison sentences?

I think they will put in place the equivalent of the FCC. It may not happen until after something really bad happens - but it will happen, and them all LLMs that aren't air-gapped will need to be independently tested.