We have MS trying to move Xamarin into a much more capable x-platform tool chain. Windows, iOS, Android, macOS (eventually) and even web is on the roadmap somewhere.
And, as of Sept 22, we get the announcement that the Swift team has released a toolchain for Windows.
What remains unclear with the both toolkits is how easy it will be to design a UI in a cross platform way.
Some tools already do work x-platform, like Elements compilers.
But they require you to have different custom UI’s per platform usually made in the platforms “preferred tool” – Xcode on macOS and VS on Windows
If I wanted to use those tools I’d already be using them and have a single common “platform abstraction layer” then my common business logic I can just share and a custom UI per platform.
IF these big guys ever figure this out it could put a lot of pressure on a tool like Xojo.