All merchants who sell anything, which I believe is all of them, have something that is in demand. The demand must be greater than zero for them to stay in business. If you as a merchant need 30K to live a year, then you must make 30K profit each year. That can be from selling 1 print for 30K or 3000 prints for 10.
But if demand is zero, you make zero. Figuring out how much demand there is for a product is the absolute heart and soul of any business. High demand and low supply = high priced goods. High supply and low demand = low priced goods. How many people do you know, personally, who have ever purchased a landscape photograph? Let's exclude poster-buyers. I mean a real person who bought a real photograph from a photographer who takes landscape photos. I don't know about you, but for me, the answer is zero. Ultimately there are things in life which we do simply for fun. Those avocations will never become our vocation.