This has always confounded me when presented as a first choice when developing something with value. I can't think of any other fields with so much practical value where all participants are practically shamed for not giving away something that is identical to their most commercially valuable skill.

Most of my life has been financed by closed source products I developed on my own to fill a real need and others had it too. Had I given them away, the best I could have hoped for was what, a job offer?