We could be plunged back into the horrible era that was ... the 2010s! There wouldn't be a global collapse if TSMC was lost. It'd be an inconvenience that sets the semiconductor industry back a decade or so. Most advanced technology hasn't had time to have an impact on the global economy yet and 98% of people won't notice much in practice if all the TSMC foundries exploded tomorrow. There'd maybe be some shortages while other companies build new foundries - although even then it isn't a given people would care. China seems to be about to flood the market with manufacturing capacity.