Present day authors are marketers too. It is just the nature of the industry today. I took a class about 'Writing to Market' at the writers conference. The presenter had fascinating procedures for writing to maximize revenues. She backed up her presentation with data. Write what people want to read as shown by analytics. She earns a decent salary from her writing and it is growing each year. I felt her energy and was excited but after the class I realized that that is not the way I want to write. I will probably use some of her techniques in the future but I'm never going to write five books a year and I don't want to write to someone else's formula. It works well for her but would not work well for me. And that's okay.