“I want to kindle the creative spirit in others,” Townsend told me over e-mail. “My games are open-source because I want people to learn from them, or use them to build their own things.”
Notice how open sourcing their product had no impact on their sales. I'll be so happy when defensive software licensing dies after people realize code isn't worth protecting.
(Some code is worth licensing. It was most of Id Software's revenue stream. I'm referring to all other code that isn't designed to be licensed, which people still insist on being paranoid about protecting.)