Those reasons are possible, but in the companies I've worked for the resistance to open-sourcing code is mostly just fear: • the competition might use our code

Those reasons are possible, but in the companies I've worked for the resistance to open-sourcing code is mostly just fear: • the competition might use our code to make their products better than ours • our code is obsolete or just plain terrible, and could hurt our company image • we might have to spend a ton of time supporting users that made changes to the code • if the community does a better job with the code then we might get fired