Art is a chance. A chance that you will make something that resonates with someone. A photograph is a chance. A piece of copywriting is a chance. A painting, a sculpture, and a book, are all chances.
That means that skill is the measure of probability that one of your pieces will work. A screenwriter who makes a hit might be lucky, a screenwriter who makes 7 hits out of 10 attempts is skilled.
This means that chances of success are related to the quantity of your work and the skill level. That lower skill can be made up for with higher quantity. Then as you see success, your work can be calibrated to fit the desired outcome better and better and your skill rises allowing more effort to be placed in each attempt, likely increasing the chances of producing a “masterpiece”.
If you’re an artist, quantity is important at first, later in your career, quality matters. There is no point in spending a huge amount of time and effort in details that don’t matter, developing skill is the same as figuring out which of them do.
P.S. I use the term artist loosely. A salesperson is an artist in gaining interest and negotiation. A doctor is an artist in diagnosing and treating a patient. If you can’t write down the specific, detailed steps to do a piece of work, then you’re likely an artist.