So it's ethical to overcharge for a lamp, but unethical to overcharge for healthcare?
What is your definition of over charging?
Buyers don't buy based on price alone. You need to take trust, after sales service into account.
Let me rephrase the question. Is it ethical to overcharge for a lamp, but unethical to overcharge for healthcare?
The term "overcharging" cannot be easily defined. It is fair to allow people to make a profit off of the time and capital they invest in their business.
The only true way to "overcharge" someone for something is to charge a price that is above the market rate, but if you charged this much then you would not be able to sell your product/service.