Which law? Seems like it is under EU law.

> In law, a monopoly is a business entity that has significant market power, that is, the power to charge overly high prices, which is associated with unfair price raises.[3] Although monopolies may be big businesses, size is not a characteristic of a monopoly. A small business may still have the power to raise prices in a small industry (or market).[3]

All countries with a working democracy would class Apple as a monopoly as it has significant market power, enough to distort prices.

https://en.wikipedia.org/wiki/Monopoly

Not for the nerd definition of iOS as a market.

The market is mobile devices.

A market is the set of things which are fungible substitutes for each other. Essentially every brand of gasoline is in the same market. By contrast, gasoline and diesel are separate markets, because some vehicles require gasoline and can't use diesel and others the other way around. They're not substitutes when your vehicle can only use one of them and you can't get out of it by trying to claim that the market is all types of fuel.

Now suppose you have an iPhone and want to download an app, or want to distribute your app to customers many of which have an iPhone. What substitute for Apple's store is available to do that?

I must have missed when I could install Android apps on iOS (if Apple actually allowed users to install their own software there's a 99% chance this would exist by now funnily enough).

Yea defining the market is 95% of anti trust cases. But asking yourself 'if Microsoft did what Apple is doing' should be enough to show at some point, it is a market.

> More specifically your question is like asking what if you have a car that requires diesel, what substitute is available to let you use cheaper gasoline?

It's like asking what the available substitute is for diesel fuel from Shell, to which the answer is diesel fuel from Chevron, BP, Sunoco, etc.

So now what are the available substitutes for distributing apps to devices that require iOS apps and can't run Android apps?

The same way you have a Playstation and don't want to pay Sony for the game.

I don't understand what makes people think Sony should get a pass here either. If you want to port Blender to PlayStation so people who buy a PlayStation can use it for 3D modeling then what business of that is Sony's?

We aren't talking about nerd definitions. We are talking about the real world.

Apple can change their rules and it materially impacts the market.

The real world is that outside US, Apple hardly has a monopoly in mobile phones.