If you do good work, they will come.
A lot of good people live by that belief. But in my own experience and within of the range of research I did for an upcoming project, it looks like this is not true.
I guess most of us have that friend that is creating either great music, having awesome business concepts or doing some other part of great work for the sole purpose of creating. We have been told, that putting out good work will make the audience come and find you. This might have been true back in the days. Today good work is everywhere because technology helps people creating and so many people can do great work now that was not possible without computers and stuff.
But due to this fact there is a total overload of information and there is a very small chance that people who are looking for what you do, find you without you putting in the work into the marketing side of things too.
Promoting your art and selling it is not bad. There is no selling out if you stay true to your craft and vision. Selling out is doing whatever works in order to get the money.
So the question is not if you should focus on doing good work or marketing. In order to be successfull with your art, you need both.
In order for our work to have an impact, it must first have an audience.