You seem to be conflating 2 different things. Apple’s OS proficiency and the associated technologies they support on their OS and Apple’s dev tools proficiency.
People use Apple’s dev tools because they are the only/best way to deliver apps on Apple’s OSes.
If we changed the situation, so that Apple Dev Tools could be used to create applications for non Apple OSes, or non Apple Dev tools were first class citizens for creating Apple apps, I bet the vast majority of people would use the non Apple dev tools to create both Apple and non Apple apps.
What’s keeping Apple Dev Tools in the game is their privileged position in the Apple OS ecosystem.
People use Apple’s dev tools because they are the only/best way to deliver apps on Apple’s OSes.
If we changed the situation, so that Apple Dev Tools could be used to create applications for non Apple OSes, or non Apple Dev tools were first class citizens for creating Apple apps, I bet the vast majority of people would use the non Apple dev tools to create both Apple and non Apple apps.
What’s keeping Apple Dev Tools in the game is their privileged position in the Apple OS ecosystem.