Not an expert on semiconductor at all, but allow me to put it this way. Suppose some natural calamity destroys everyone outside China. Is China, with its 1.4 billion people and existing expertise in semiconductor and related industries, thereby doomed to technological regression, never able to produce semiconductor again once stocked foreign materials run out or foreign machineries wear out? I have a hard time believing it.
In my opinion US goals are the following
1. To cramp China development in
Digital Economy. Semiconductor is instrumental, like is AI, data centers, etc. The target is what China calls "Digital Economy Revolution", the foundation of techno/economic power in 21st century. US wants to keep the leadership and slow down and even straight damage China as much as it can.
2. Decouple Chinese Digital Economy from the rest of the world (in the very self-referential western definition of World). Here we are still at the beginning, but much more is expected. Chinese high-tech firms will have a hard time selling their products outside China. At least this is the target IMO.
3. Force the so called allies to be even more loyal and submissive. This is the base for a successful friend-shoring policy. US realizes that full on-shoring is not possible, so the target is to friend-shore: let others (Japan, Taiwan, Korea, etc) to do the hard work and also on the cheap, but ensure they will promptly abide to any new US
rule. So they will have their cake and eat it too. One of the strategic ideas behind pushing TSMC, Samsung, etc to open US fabs is to create leverage to better blackmail them when needed.
Of course this does not mean this will succeed. It never succeed in history, like for instance when US itself was blocked from acquiring European technology in 19th century, very possibly (and hopefully) it will
not succeed today.