[diegogcouto]

I agree with you and it's a very interesting point, but I also think that there is another one.

Let's suppose that you're developing some tool that could solve problems of a lot of people. It's natural that you try to sell this to them (there isn't free lunch).

Getting paid only by services, in my opinion it's not that sustainable, because you'll have costs with this service and you already have other costs with development. To start making some profit, the price of the service has to be high.