If you do not hoard your ideas, and neither do I, then we can both benefit from the ideas of the other. If I can access the ideas of a hundred other people at the cost of sharing my own ideas, then I profit; no matter how smart I am, a hundred other people working the same problem are going to be able to produce at least some ideas that I did not think of. (This is a benefit of free/open source software; it has been shown experimentally to work pretty well in the right circumstances).