The cost of doing business is customarily factored into the price of goods, although some people have taken advantage of the potential of extra profit in "shipping and handling charges" ever since mail order became possible.
To set your price of goods at a competitive level then inflate your shipping charges gives you an unmerited advantage over sellers who set their price of goods at a competitive level and do not gouge on shipping.
Sooner or later, the consumer catches on and shops with the sellers who have the best overall prices and service.