True, though money can buy influence and the opportunity to obtain power.
America's elected leaders also have power to punish & bring oligarchs to book legally, but they mostly interact symbiotically, exchanging campaign contributions and board seats for preferential treatment, favorable policy, etc.
Putin can order any out-of-line oligarch to be disposed of, but the economic & coercive arms of the Russian State still see themselves as two sides of the same coin.
So, yes: coercive power can still make billionaires face the wall (Russian revolution, etc.) but they mostly prefer to work together. Money and power are a continuum like spacetime.