It’s not only hubris — I think it’s actively counterproductive. The US could choose to:

(a) Sell many billions of dollars of fancy chips to China, thus bringing in billions of dollars of money and billions of dollars of trade balance improvement. And let China continue to build models quickly when they seem oddly happy to export the trained weights for free.

Or

(b) Decline to do so, thus reducing exports and very very strongly encouraging China to do everything in their power to avoid needing to depend on our chips.

In exchange for (b), what do we gain? A temporary advantage in model training and availability?

This admin is super in favor of isolationist policies right now. Whatever can bring in the most bribes. To the detriment of 99% of the public.