I just... completely don't understand the appeal of Swift beyond it being Apple's in-house language. I was excited for Foundation to become open-source. Using a language you'll really only find in 1 environment is a negative. I'm going to go feel ashamed for not getting excited about a language now. I should be celebrating "more languages", but Swift is just Apple. No one outside Apple chooses Shift unless they want…
If they just had a proper cross platform standard library and package manager it might be more successful, it is a pretty cool language. But the north Korean esque closed apple ecosystem makes that impossible, all of that is intentional.
Is it just that the maintenance cost is not worth it? Or would it threaten its ecosystem in a way that I don't understand?
It would seem that making Swift cross-platform would make Apple's ecosystem more accessible to developers. The barrier to entry would be lower if developers only needed to learn the APIs and not a whole new language and its tooling too. This would help the ecosystem stay healthy for a longer time.