[yiyus]

You must make possible for other researchers to reproduce your work, but that does not mean you have to give it to them for free.

I work in an university, but in close collaboration with industrial companies. We use models that we explain with detail in our papers, so that other researchers can write their own implementations and maybe confirm or disprove our results. But we do not make the code available.

This is what I see, that does not mean I think it is the best approach. I would really like to release all the code I write. It would make research advance faster, and I do not think that it would harm the company who pays for my work in any way.

But they pay, and they have strict policies. At least they allow me to share most of my code with other researches in a personal basis and write papers about it. I am quite sure that, if to publish papers I had to always share the code, they would just directly hire me or someone else to do it and there would be no papers at all.