That might be one big problem Swift has today:
It wants to be used everywhere, but its development has an exclusive focus on Apples needs.
See [Second review] SE-0386: `package` access modifier for a recent example, or Any interest in Linux improvements? Has Swift for Linux caught up yet? or Stability of Swift on Windows?.
Looking further, there is a whole bunch of additions for SwiftUI, like [Accepted] SE-0279: Multiple Trailing Closures.
Also, there has been a significant change on how evolution works.
We started with "send in your wishes, we'll try to fulfil them" to "if you seriously want to propose a change, write an implementation first" to "hey, someone from Apple here, we created a feature which you can already use with the —needed-for-next-wwdc flag, let's quickly finish the formal proposal stuff".