Hi Candy!
Yes the sentence seems accurate to me. I'll mention this one nuance though. If you use demand singular, referring to multiple artworks and multiple men, it refers to the general concept of demand and supply. Hence he bases his artwork on what his general clientele of Rich men want. If you use the plural of "demands" it translates as: "based on rich men's requests.".
To cut it short, demands (specific orders/requests) vs Demand ("market" based demands; taste of the rich men that influences the general supply and demand of this type of artworks).
Hope this helps!