Power is always loaned, and always beholden to someone (or a large group of someones) else. That's what makes it power: the ability to get other people to do what you want them to. If they don't do that, you don't actually have power, while if they do, you've got the power regardless of what the formal power structures (which are often misdirections anyway) say.

The rest of your post is largely true, but also applies to billionaires. They derive their power from people being willing to trade money for the goods and services produced by the assets they own. When people cease to make that trade, their money and their power evaporate. Just look what's happened to the shareholders of Kodak, Xerox, Pan-Am, GM, Sun Microsystems, Lehman Bros, etc.

Note also that systems without billionaires have existed, and have often been worse in terms of distributing power to many people. See eg. Soviet Communism, where power rests in the Politburo, and the local party apparatchik holds outsize sway over everything regardless of competence. Or even post-WW2 U.S, when the top marginal tax rate was 90% and executive compensation was far lower because there was no point in paying a lot when the government got 90% of it. Corporations instead compensated their top execs in-kind: usage of private jets, corner offices, ability to influence what every American thought through advertising and mass culture, influence on policy makers. Orwell's 1984 and Chomsky's Manufacturing Consent were about the 1945-1980 period, not the post-Internet era. Power was significantly more centralized during that time period than it is now.