Being altruistic could be one of your best business ideas. See WordPress as an example. Millions of blogs are running on this platform and there is a new business for everyone. People who customize themes get “a piece of the pie” and so are the designers and developers of plugins and the people responsible for the SEO.
I am sure, a lot of people who work on WordPress development got a lot of side job because of their expertise.
The lesson is this: sometimes it is better to build a technology and give it up for free to create more business opportunities.