An artist who sells work and pays income, sales and business taxes as an artist must be involved in the business end of art, keeping records, usually employing an accountant for taxes, and is required by law to have a business license. A resale license is required. A good deal of time and many phone calls are often spent with someone trying to decide on a piece. This is work time, just as is the time spent creating a piece. A great deal of art is just not commercial in nature and cannot be sold easily.
Most artists do much work like that, as well as some work that has public appeal.
Most remains in the studio.