Marketing And Staying Focused

I was reading an article this morning on artprintissues.com by Barney Davey, I'm sure its advice I've heard many times before but for some reason it resinated with me this time.  Maybe because while flipping through TV channels last evening I saw these singers from the 50's and 60's singing their popular hits and couldn't help but wonder how one song could continue to make money for them year after year after year.  Its the same goal for artists isn't it......produce a work that will sell prints year after year.
Watching Secret Millionaire last night with artist Scott Jacobs whose name meant nothing to me (and I had to google), but whose giclee prints I discovered, can sell for thousands. 
Barney Davey:  "By not prioritizing their marketing, artists can find themselves pulled in too many directions at once when trying to get their work to market. It is common for an artist to want to make different kinds of art; that is they might be interested in working in watercolors, oil, pastels, or even sculpture or mixed media. Or, perhaps they want to do landscapes, abstracts and portraits.
Entertaining imaginative impulses is great for a creative person; it keeps the stimuli at a high level. Regrettably, it is a snare and a trap for the artist serious about marketing their work. There is a need for the artist to focus on a distinctive style, or aesthetic. Consumers, art dealers, and art galleries use continuity to help them understand the artist and their work."

Its ingrained in me, my mother telling me as a young person that I would never be happy because I flit from one thing to another.  Was I just 'entertaining imaginative impulses'?  I would get spanked for rocking in my bed at night....I swear I could move a bed across the room in my sleep.  And teachers who would say, she can't sit still and she's smarter than this, when my grades continued to be subpar all through school.......why I hated writing book reports because I could never stay focused on the words in a book, I still find it difficult and do not enjoy reading.  Why I'm happier doing physical work rather than sitting quietly with a project..... why I prefer murals over the easel (although I love both).  Why I drink to quiet my brain.
I have to wonder...... is the frustration that I always feel just lack of discipline, or a trait of the creative person,  or is it something else.  Has ADD been around longer than has been talked about.  Because like my teachers.......I know I'm smarter than this.
I think its time to find out.