I can buy something else. In fact I did. The problem is that if you are making a product which will be consumed from a phone you have to support iPhone users and do everything Apple wants you to do.
If you're selling an app, it's even more important to support iOS users because the App Store is responsible for three times as much revenue as the Play Store[2].
[1] https://www.statista.com/statistics/266572/market-share-held...
[2] https://www.patentlyapple.com/patently-apple/2020/01/in-2019...
> Courts do not require a literal monopoly before applying rules for single firm conduct; that term is used as shorthand for a firm with significant and durable market power — that is, the long term ability to raise price or exclude competitors. That is how that term is used here: a "monopolist" is a firm with significant and durable market power.
[1] https://www.ftc.gov/tips-advice/competition-guidance/guide-a...
You quoted selectively. It goes on:
> Courts look at the firm's market share, but typically do not find monopoly power if the firm (or a group of firms acting in concert) has less than 50 percent of the sales of a particular product or service within a certain geographic area. Some courts have required much higher percentages. In addition, that leading position must be sustainable over time: if competitive forces or the entry of new firms could discipline the conduct of the leading firm, courts are unlikely to find that the firm has lasting market power
It is clear that A) Apple is not a monopoly and B) the market is very competitive
(Yes, yes: Apple has just cut the rate for small devs. The big sellers still have to pay 30% though.)