Even after the AI bubble pops, ASML's machines will be useful. People generally want computers and chips, preferably the fastest an latest-generation ones. The ROI may be lower once the bubble pops, but the machines will earn themselves back eventually.

Once the bubble does pop, ASML will be in trouble, though. It'll take a couple of years for their latest machines to generate as much interest again, so the effects of the market collapse will echo for years after it happens.