The notion that people contributing to Open Source don't get paid is false. Contributors to Open Source are compensated for their labor; not always with financial capital (i.e. a paycheck) but certainly with social capital. Social capital is a rather vague and intangible concept so let me give some examples. If you know someone at a company where you are applying for a job and this connection helps you get that job, you have used social capital. Or if you got a lead or a business opportunity through your network, you have used social capital. Or when you fall on hard times and you rely on friends for emotional support, you're also using social capital.
The term "social" refers to the fact that the value is in the network of relationships; they can't be owned like personal assets. Too many people believe that success in life is based on the individual, and that if you do not have success in life, there is no one to blame but yourself. The truth is that individuals who build and use social capital get better jobs, better pay, faster promotions and are more effective compared to peers who are not tapping the power of social capital. As shown in the examples, social capital also translates into happiness and well-being.
Most Open Source contributors benefit from social capital but may not have stopped to think about it, or may not value it appropriately. Most of us in the Open Source world have made friendships for life, have landed jobs because of our contributions, others have started businesses together, and for others it has provided an important sense of purpose. Once you become attuned to spotting social capital being leveraged, you see it everywhere, every day. I could literally write a book filled with hundreds of stories about how contributing to Open Source changed people's lives -- I love hearing these stories.
Social capital is a big deal; it is worth understanding, worth talking about, and worth investing in. It is key to achieving personal success, business success and even happiness.