What you’re describing is true, but the iPhone runs general purpose software. They don’t have to give away their own features to their competitors and people who aren’t their customers, and it’s more valuable to them as something they took the time to develop as a point of differentiation to give their customers a better experience than they would otherwise have.
An iPhone can already send files or stream media to all products provided you negotiate the protocol by which you do it and the software is available or you write it yourself. YouTube has Google Cast built into it, which you don’t have to use with an Apple TV because AirPlay will work, but if you say wanted to put video from your phone up on a Samsung smart TV, it’s an option. If you want to transfer files from an iPhone, you are not lacking in options, but if it’s to another iPhone or a Mac, AirDrop is just one of those options.
An iPhone can already send files or stream media to all products provided you negotiate the protocol by which you do it and the software is available or you write it yourself. YouTube has Google Cast built into it, which you don’t have to use with an Apple TV because AirPlay will work, but if you say wanted to put video from your phone up on a Samsung smart TV, it’s an option. If you want to transfer files from an iPhone, you are not lacking in options, but if it’s to another iPhone or a Mac, AirDrop is just one of those options.