I'm on the opposite side now. I don't work for a software development company. The people who make us money have to support software development. The development department is considered a cost center. That doesn't mean that I should pay them.

For the most part, what you make isn't derived from how much revenue you make your company. It's derived from what the market will bare. Even if you are independent, people who are hiring you are going to try to find the largest spread between what they have to pay for development and the profit they can make based on the development.

On the other hand, what are the real cost of being an independent developer? Health insurance, a computer (that we would probably have anyway) and any development tools. We can usually get away with Fred development software.