"Herschel I. Grossman (1995) and Stergios Skaperdas (2001) both consider mafia as an alternative enforcer of property rights. Using a model with two actors (a self-governing community and mafia) and potential robbers, Skaperdas (2001) shows that in the absence of an enforcer of property rights, mafia can represent a sort of second best solution"

I do agree, that mafia act as a government. But there is still quite a difference to a democratic government. It is more a olygarchy/despotism.

But I believe our roots of government back in the middle ages, when feudals conquered new peasants to profit from them, were very alike. And there might be still characteristics in our institutions from that legacy. People definitely view it that way, when they pay taxes ...