I think you're exactly right about this! But just to provide some insight (which you probably already have) into the mind of a different kind of person: I can

I think you're exactly right about this! But just to provide some insight (which you probably already have) into the mind of a different kind of person: I can both recognize the truth that marketing is critically and synergistically important, and also have just a deep seated allergy to it. I have concluded that being a freelance / independent developer or even a very early stage startup developer is not a great fit for me for this reason. I thrive more when there is lots of work to do that is not deeply attached to marketing a new product.