> In Economics 101, I learned that in a free and fair marketplace, it was impossible to maintain an outsized profit, because competition would always show up to take part of that profit.
What you should have learned is that in an idealized, perfectly rational, perfectly competitive market this is true, and you should have also learned that such markets do not exist in reality, not least of all because rational choice theory does not accurately model human behavior, but also because perfect competition is not an attainable condition.
Yes, many competitors show up, and are promptly purchased for quit a bit of cash and/or stock. Many of these purchases shouldn't make it past anti-monopoly laws, but the regulators are captured.
However, the oversized profits are a significant source of incentive for investment in alternatives. Kharma will catch up.
This is all "perfectly spherical cow" economic theory which does not apply in reality. Do we really have a free and fair marketplace? Where's the competition that's shown up and been able to get any kind of substantial piece of the outsized profit of Facebook, Apple, Microsoft, Google?