I think the reason is that America & China for the most part are also in AI arms race combined with an AI bubble and neither side would wish to lose literally any percieved advantage to them no matter the cost on others.
Also there is an immense lobbying effort against senators who propose for a stricter AI regulation.
https://www.youtube.com/watch?v=DUfSl2fZ_E8 [What OpenAI doesn't want you to know]
It's actually a great watch. Highly recommended because a lot of talks about regulations does feel to me as mirrors and smoke.