Business leaders have an actual score they can point to as justifying their choices and actions. Profits go up, the stock rises, customer sat has risen, and therefore the previous choices have paid off. Warren Buffett makes a stock pick, and at some point it pays off or it doesn’t. Jony Ive and Tim Cook remove the headphone jack from the iPhone, and either they sell more or they sell fewer. The numbers don’t lie and all that.
For a singer or director, there’s nothing like that. There’s no score afterwards. One person will tell you what you did was great, and another will tell you it was garbage. Who are you going to believe? There are no hard numbers there. It’s dependent on their respective tastes.
You probably don’t want to go by the businesses numbers either, especially if you consider what you’re doing to be art. Summer blockbusters make a lot of money. Is that artistic success? One opera draws larger crowds than another. Is that success? Maybe/maybe not.
You’ll have to define it for yourself. The alternative is not knowing what you stand for and an emotional dependance on other’s flitting tastes.