It actually just means that the business needs to charge more for whatever it produces. For a restaurant, for example, the general guideline seems to be that 30

It actually just means that the business needs to charge more for whatever it produces. For a restaurant, for example, the general guideline seems to be that 30% of the costs are labour. So increasing the wages by 20% means costs increase by 6%. If a business can't survive that then the business simply isn't viable. Why exactly should we expect people to work below a livable wage just to keep a non-viable business afloat?