Unfortunately, there isn't enough competition for this to be true. In many markets the largest incumbents are able to build a moat to stop smaller, smarter companies from competing. Sometimes this is regulatory capture, but it can also be that the market is a natural winner-take-all market, and in that case well-thought-out regulation can be necessary to enforce competition.
Venture capitalists shy away from funding companies that want to compete in a well established market. They view it as a race to the bottom with no huge payout.
Once a company is large and well established, it can be as bloated and inefficient as any government, and it will extract rent with it's IP, real-estate, and means-of-production for decades before it has to worry about failure.