Yes there is the control end too. To develop software internally in a company you have to show there it gives you a proprietary advantage that other companies do not have and cannot buy. So that leads one down the confidentiality path. Every stupid thing then gets justified based on confidential and proprietary even if it is a stupid argument (not saying it is always a stupid argument). Imagine then saying let's open the software. Might even be the correct thing to do but then you'd have to admit your proprietary arguments were BS.

Then even if you did that, you would have to do a deep code audit to remove anything that could potentially be an issue. Then you'd have to run that all through legal and up the flag pole to executive level. Then they would ask, why are we doing this. You had better have a good answer.