You're absolutely downplaying what a good barista does. They don't stop when they clock out. The same way a "knowledge" professional doesn't. Using wage labor jobs in the US as a metric for what is/isn't a high earning wage isn't a valid metric for who is or isn't a professional. I know plenty of people who earn more than baristas at Starbucks, but I know more baristas that are smarter and passionate about their jobs than some of the highest earners I know, and they don't work at chains, they work at local places and own their own places. So while sure hourly employment can often times "lower stress" it absolutely doesn't mean it's lower stress than any other salaried or "knowledge" work.
Like for real you don't think it takes knowledge in a culinary field?