OK but why should the compound be run by Zuck, and not e.g. the security force? Why not cut out the middleman?

Well, I am not an expert in governance. I just offered an example to how security forces would be compensated when there is no currency. One could imagine multiple layers of security forces... or some resources under the direct control of Zuckerberg and his direct reports, etc.... Granted, it would be a more dangerous and less fun world for Zuckerberg to live in, but I answered a hypothetical question.