I think what is much more interesting is what OpenAI and Google will do. There's probably some threshold of signatories where the companies in question do not fire everyone when they decide they want the DoD's business, the question will be how many people have to sign to cross it... and will enough people sign.
I don't think Google would bat an eye at firing 500 people to secure a DoD contract, but would they fire 5,000?
xAI is a pure choice. Their people have the ability to work at Anthropic but choose xAI.