In 6 months TMSC US foundries would grind to a halt without consumables from TW who still has many sole source suppliers. The reason for CONUS TSMC fabs is because that's all US industrial policy can really manage, CHIPS never pretended to be able to reshore the entire semi supply chain (unlike PRC) and until US does, or at least reshores everything sole source off TW, will remain exquisitely vulnerable.

Also TW politicians have objected to notion they'd vaporize their fabs / golden goose. That meme started by US Army War College + Colby who said US should blow up the fabs, as in it shouldn't be a TW decision. Which TW have rebuked said they will defend against US attacks. Also other shenanigans like when US suggest they would paperclip TW semi engineers, and TW basically said there's no way they'd send semi engineers to safety before children. AKA TW not retarded, they know not to toast their golden goose, because golden goose for PRC still gives TW leverage even if TW forced to capitulate. They'd still rather be wealthy semi producers than pine apple farmers under PRC.