“Fame, money and the size of the market are not very important to me. What is, is writing a book that is worth doing and then publishing it.” Aidan Chambers
Writing something important is what is important, not the sales per say. Sales are a reflection of the acceptance and dissemination and adoption of the ideas in the work.
Creating something meaningful, crafting something beautiful. These are where the effort and excellence lies, and something under the control of the creator. Commercial success is not.
Too often we judge an artist by record sales, or by where they are on a particular list reflecting downloads, or some other metric that is the output of luck, marketing, current tastes, and various other exogenous and shifting factors. Great words remain great words over centuries, independent of the current fashions.
Focus on doing good work, on making something worthwhile instead of impressing the masses or chasing a buck. It is more fulfilling and ultimately rememberable.