Honestly, swift playgrounds was a massive surprise when I saw it released. I've been a developer for years and never saw Apple moving in that direction. Now in terms of Xcode, anyone who's spent time using interface builder knows it's far from usable on a touch screen. If Apple plans to make a full IDE available on iOS, I could see them doing it incrementally, like adding support for commandline programs in iOS 11 and slowly adding more features. Next 1-2 years? No way. 5 years is a good possibility though. It all depends on what we see them do with swift playgrounds in the future