China eventually gave up the plan in 1960's not because it didn't want to but because the balance of the power weighting over to west China. In 80's and 90's both agree to make peace given the premise that both sides belong to China.
TSMC was a product of industry policy from None-democratic China government. The founder Morris Chang , an American born in the west China ,never visited China before 50 years old.
Both China (before 90') and west China used to want reunification , by force or not. China changed a bit later. The motivation of west China to invade China has little to do with chips although US thought that's the critical incentive. West China will still let TSMC provide the chips to the world in case it would have successfully invaded China in my view.