Companies would secretly use self-hosted models internally because it would give them a enormous cost advantage.

Sure, companies can indeed do illegal things

But how would the actual weights it be made illegal without violating the 1st amendment?

By ignoring the 1st amendment? The US has a tendency of ignoring its constitution whenever it's convenient.

Don't be glib, the 1st amendment is taken VERY seriously.

Im not sure if you’re joking or not.

- the US strictly regulate cryptography https://en.wikipedia.org/wiki/Export_of_cryptography_from_th...

- some prime numbers are considered illegal https://en.wikipedia.org/wiki/Illegal_number#Illegal_primes

I don’t think banning open weight is that far fetch compared to those