The fact that this has static typing is a huge difference to "just improving" ruby/python. That approach couldn't come close to getting the same early-error-catching dev experience, and performance. And amongst static languages, Apple wasn't likely to recommend C++ as simple, were they? And Rust/D are also quite low level, nor do they have the Objective-C legacy to consider. So really, you're probably left with C# (or maybe Java), and those are so old and large (esp. the libraries) by now that they're unlikely to naturally port to Apple's environment.

Frankly, a bit of a clean up every decade or two is not exactly often, right?