I agree that wrapping can and does work in most cases. But then there are times when it doesn't work without introducing a lot of complexity and/or inefficiency

I agree that wrapping can and does work in most cases. But then there are times when it doesn't work without introducing a lot of complexity and/or inefficiency or without limiting design choices. How will the new concurrency/parallelism facilities they are planning for Swift work with libdispatch queues? Will they want to build on GCD or not? Will whatever they do work for Objective-C just as conveniently? That's an open question in my view. For an example why wrapping cannot work efficiently in all cases look no further than Python 2 vs Python 3 strings. They are conceptually too different. With enough "waste" of resources everything can be wrapped. I don't know how React Native works. But React.js uses a virtual DOM that effectively doubles memory usage. That's what gives them the freedom to use a completely different approach to updating the UI. I put "waste" in quotes because sometimes paying for a more productive and simpler system with higher resource consumption is the right thing to do. But in other cases it is not.