In my opinion, not yet in the case of Amazon. As I listed, they numerous competitors, and one hardly needs Amazon to obtain their goods. It is trivial to throw up a non Amazon retail website.

At least I can think of many more businesses where consumers do not have an option and extremely high switching costs that need to be dealt with first. Such as a home’s wired internet service provider. That is an unfair advantage that needs the government.

I would say the iOS/Android duopoly is another big one.

The inconvenience of needing to go to a different website (which already exist) is not.