Apple haven’t invented screen mirroring though. There are plenty of pc and Android apps which enable it. It’s just Apple are the only ones allowed to do it on their own OS’. I don’t care either way about iPhone mirroring - I use it but whatever, but the simple fact of the matter is that iOS and even macOS aren’t vacuum cleaners, or TV’s, they’re operating systems for computers and smartphones where a big majority of people live their life. They’re so prevalent that it’s almost impossible in some countries to live without one. Digital infrastructure is based around one.
It’s not a case of “use the other one”. it’s not a case of “it should be up to Apple, they invented it”. It’s too big. There are two. Percentage and market share don’t matter - what matters is that users, businesses and makers all have the same opportunities to profit as the makers of the os or the device. They don’t need to give secrets or any of the other assumptions people are making - they just need to stop giving themselves a leg up to sell their stuff over everyone else. It’s illegal, and there are many many cases of similar situations across the world, including the US, where monopoly behaviour (I know I know - but nonetheless it IS monopolistic behaviour, whether it’s a monopoly or not), or other similar utter control of a market has resulted in companies being broken up.