I think profit share is not a bad idea, but to make it fair, it should also involve some degree of risk sharing. Counting up the costs of opening a coffee establishment (is it a roaster as well?), it's not as high as some other businesses but there's rent, equipment, seats and tables, etc. If every employee and the owner was a member of something like a LLC, what would the buy-in be? I have no idea, maybe $10K each or something like that? Most of that would be lost if the business failed, so it would provide a nice incentive, and once cleared, a steady stream of income.

Of course a short-term employee (summer, tourist season, etc.) would probably not be interested in that arrangement, and would prefer a good steady wage.

Employees spend half their waking hours at work. That's a huge opportunity cost. I don't get where the idea comes from that they take no risk!

Profit sharing can be things such as giving a bonus when sales are good. No need to make things as complicated as possible. Lots of other sectors give bonuses, restaurants/hospitality almost never.