It is now more of a bureaucratic republic (whereas US to me seems more like a corporate republic, or corporatocracy), i.e. is governed by and in the (broad) interest of the statesmen, not businessmen.
Funnily, one of oligarchs who was put down by the state is the famous Khodorkovskiy, whom physics likes to refer to as "effective businessman who tried to oppose Putin" :) The Khodorkovskiy's case was in its time instrumental in transfer of power from oligarchs to the state.
This is by the way why all the "personal" sanctions U.S. imposes on Russia now has no effect. Because their targets either have no leverage over power or are appointed figures.
Like Deripaska - has no power (the 2003 power transfer), and Sechin is appointed a CEO of Rosneft, he doesn't own it.