the people with all the firepower won't let you buy your own private military (or develop your own weapons systems without being under their control). The end-of-line power (violence) is a closely guarded monopoly.

But, on the flip side, coercive power cannot stand on its own without money too. The CCP's Politburo know beyond a doubt that they have coercive power over billionaires like Jack Ma, but they try to accommodate these entrepreneurs who help catalyze economic growth & bring the state more foreign revenue/wealth to fund its coercive machine.

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.