We have a good old fashioned concept of "relevant market".
> A relevant product market comprises all those products and/or services which are regarded as interchangeable or substitutable by the consumer by reason of the products’ characteristics, their prices and their intended use.
Are we able to substitute browser engine or app store in iOS? If not, then its app store itself can make of a single relevant market. This is so obvious to the level that even Apple knows they cannot avoid, so they're trying to make an argument that app store and browser engine are technically inseparable system service, not an interchangable product. (I strongly suspect that this is one of the reasons why we cannot get standard 4~6 weeks browser updates for Safari, decoupled from OS updates) EU doesn't seem to be very happy with that argument so they passed the Digital Market Act in response. And US is preparing a bipartisan bill similar to DMA as well.
Yeah, I know the actual process for defining market is much more complicated but this is the basic idea. Antitrust investigation is a largely economical, data driven process and you cannot simply say "Even in their best market, the U.S., iPhone holds just a smidge over 50%". I won't assert they're in a monopolistic position, but many regulators (especially in EU) believe in that.
> A relevant product market comprises all those products and/or services which are regarded as interchangeable or substitutable by the consumer by reason of the products’ characteristics, their prices and their intended use.
https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=LEGISSUM...
Are we able to substitute browser engine or app store in iOS? If not, then its app store itself can make of a single relevant market. This is so obvious to the level that even Apple knows they cannot avoid, so they're trying to make an argument that app store and browser engine are technically inseparable system service, not an interchangable product. (I strongly suspect that this is one of the reasons why we cannot get standard 4~6 weeks browser updates for Safari, decoupled from OS updates) EU doesn't seem to be very happy with that argument so they passed the Digital Market Act in response. And US is preparing a bipartisan bill similar to DMA as well.
Yeah, I know the actual process for defining market is much more complicated but this is the basic idea. Antitrust investigation is a largely economical, data driven process and you cannot simply say "Even in their best market, the U.S., iPhone holds just a smidge over 50%". I won't assert they're in a monopolistic position, but many regulators (especially in EU) believe in that.