Why isn't iOS devices a market? It seems that's exactly what Apple /wants/ it to be. They built a platform and now want third parties to sell on that platform so they can get their cut. How do you define market, then, if that's not a market?

> Why isn't iOS devices a market?

Same reason "McDonalds hamburgers" aren't a market. They're just a branded product within a larger "smartphones" market.

> How do you define market, then, if that's not a market?

Same way the FTC does:

> all goods or services that buyers view as close substitutes

https://www.ftc.gov/advice-guidance/competition-guidance/gui...

An Android is a close substitute for an iPhone, just like a Ford is a close substitute for a Toyota. People switch between them all the time.

Per https://www.phonearena.com/news/iPhone-vs-Android-How-often-..., a relative handful of users switch between Android and iOS. That does not seem to qualify as "all the time".