There are two effects you’re not considering.

First, if you make the best product, everyone else will leave the business, so you become a monopoly. But almost everything has what are called barriers to entry. I can’t open a microchip factory; the investment is absurd. That’s why large companies can easily buy out startups, and that’s why we constantly see market concentration. It didn’t happen before because until the 1970s, antitrust laws were serious; now they’re a joke.

There’s another important issue: in a 100% free capitalist system, it’s assumed that initial bargaining power isn’t equal, so those with more can pressure those with less, making wealth concentration more and more concentrated. Adequate government regulation can help level the playing field between employer and employee, but that’s another thing that hasn’t been improving in recent decades.