J.K. Rowling made hundreds of millions because hundreds of millions of people bought her book. Why did hundreds of millions of people buy her book while most authors struggle to get tens of thousands? Mostly because people recommended it to their friends, and their kids all passed it around school, and news stories got written about it, and major motion pictures came out, and it became a cultural phenomena where Harry Potter references snuck into every corner of life.

Look at any other billionaire and you see a similar story. Minecraft got huge because everyone was like "Yeah, I totally wasted a week playing Minecraft. No regrets" and so everyone checked it out. Facebook got huge because everyone was like "Are you on Facebook? Here, I'll friend you." Ditto LinkedIn and Whatsapp and every other social network. Uber got there because at parties people would casually say "Oh, I'll just Uber home." Google got big because people would be like "Just fucking Google it" instead of telling you the information.

Basically, when you can get your customers to do your marketing for you, you rapidly expand into the whole set of potential customers, which numbers in the billions. Provide just $1 of value to them and you're a billionaire. Most business owners and employees, by contrast, are forced to explain why it's worth giving money to them, which is a process that doesn't scale. Then you're forced to only deal with customers who will pay you more than it costs to convince them to fork over that money.

The way you can break this cycle and eliminate this inequality is to convince people to make their own damn consumption decisions and ignore what their friends say. Good luck on that.