The USA is becoming more isolationist - it is nearly oil-independent, so it's signalling pulling out of the middle east (deals with Iran etc).
But it is not silicon-independent.
So S Korea and Taiwan are totally dependent on massive US troop deployments (25,000 !! US troops by the DMZ, a whole fleet patrolling the straits by Taiwan).
Ensuring chips flow in their country is a matter of national security - so the price is probably low.