Apple never set out to create Swift. Chris partner worked on it for fun in his spare time, and when he realized it could go somewhere he went through the channels to get it turned into an official project. With that being said it was tailor made to address important issues for Apple developed. For example, it has great interop with Objective-C which was a requirement to get it adopted, first at Apple, and then with the wider community. It is also built with safety and security in mind removing lots of undefined behavior and adding null safety. It is also statically typed while JavaScript isn’t. There are a whole host of other goodies that it has that make it better for Apple developers than just adopting JavaScript. Chris partner has lots of talks where he goes over the reasonings