How much help is a PhD supervisor if you only see them 30 minutes a month?
Your supervisor's job is to be sure you're on the right track, not to do any of the work.  Thirty minutes a month ought to be more than sufficient for that.  Also, the supervisor either takes care of the administrative details or is responsible that someone else does that.  Finally, you appear to have omitted the amount of reading required of the supervisor.

I'm absolutely sure I didn't see my supervisor for 13 hours over the course of my degree, but he read every word I wrote and provided feedback without which I probably could not have finished.