>Why doesn’t someone else create a competing app that’s better and thereby steal all their business?

How do I know if the competing app is actually better? I mean, this was the advertising angle for eHarmony about a decade ago - that it was much better than competitors at actually turning matches into marriages. But this claim was found to be misleading, and they were advised to stop using it.

Could a potential customer really get to the bottom of which site is the best at finding a real match? It's not like a pizza restaurant where I can easily just a bunch until I find my favorite and then keep buying it. Dating apps are like a multi-armed bandit problem, but you stop pulling arms once you get one success. So your only direct feedback is failed matches.

This is addressed in the "information asymmetry" section of the article.