Switzerland does import a lot of its food, so expensive food is definitely part of the cost in restaurants. I don't know what the mix between food costs and labour is. But, high labour costs are part of the expense.
I'm not sure what you're talking about with your minimum income. Are you saying that certain jobs deserve a higher minimum than other jobs? Which jobs are ones where the minimum wage is allowed to be lower? If restaurant minimum wage/income is higher, does that mean that say delivery drivers are paid less?