I see your point, but your analogy is a bit off.
Working for someone in a business and being shortchanged on your hourly rate is entirely different than being an independent proprietor and offering discounts on products or services to attract clients (and your rates are self-controlled, and are above the rate of inflation to begin with).
First off, most professionals who work in companies have hourly rates they are legally tied to through the Bureau of Labor Statistics. They are also contractually obligated to their pay as well.
Many independent businesses associated with various services offer discounts… it’s intended to attract new clientele and grow a base. And usually the discount isn’t much in the first place.
It’s important that any business operates with maintaining respect for its brand, while not running it with their ego. This is a hard balance….