You hit the nail on the head. Github Enterprise is too "expensive" in attention required. While we are security-minded about our proprietary code, we also recognize that we have a limited budget for "distraction overhead." We chose infrastructure largely based on how little we have to think about it. In this case, the distraction cost would be significantly higher than the risk-weighted cost of IP theft. I still would prefer to minimize that risk, but without the additional staff and systems you mention, the only reasonable alternative we have is a local server with no internet connection. Alas, connectivity is a fundamental requirement.