*If the US government wanted, they'd dramatically slow "illegal" chip exports to China (tighten end-user lists, ultimate consignee scrutiny, sanctions on third-country distributors, firmware locks).
They don't, because the net-benefit of controlled leakage (dependency + visibility + NVIDIA scale + escalation control) beats the cost of full denial (accelerated Chinese substitutes + retaliation + price spikes in global AI supply chains).*