Good Question Roger.
I paint my designs for interior designers but the originals rarely if ever are sold. In fact in most cases I don't want to sell them because they becomes part of my proof of the original works... my design portfolio, sort to speak. Swats of colours and designs done on paper.... for a purpose.
So to answer you question.... the originals are important but they are not where the money comes from.... prints, fabric, wall paper etc....is where the revenue come from.
That's not to say I don't have many original pieces of art for sale, because I do.... and they were not created for the commercial market.
btw, love your vulture :-))
Cheers, Barbara