The GM isn't /part/ of the system - neither bug nor feature - but a user of the system... a super-user, compared to a player, with administrative override privileges. A lot of us are not just decent GMs, we're pretty good at tinkering with a dysfunctional system and keeping it going.
It's like you may be able to drive a car, and you may be able to change a flat, and you may be able to rebuild a transmission, but all three of those things don't always go together - and it might be a tad presumptuous of an automaker to expect anyone driving their cars to be able to rebuild the transmission... without pulling over.
But, yes, the presence of such a driver would be quite a feature!