It's true that C# is not as prevalent on non-Microsoft platforms as it is on Windows but there are a handful of mid-size to big multiplatform projects using C#.
e.g.
- Xamarin (multiplatform mobile apps)
- Unity3d (multiplatform games)
- Monogame (multiplatform games)
- Unreal Engine 4 (build system)
I guess Swift could fill the same gaps. I would especially love to be able to develop multiplatform mobile apps with swift since switching between ObjC and Java all the time is quite taxing.
e.g.
- Xamarin (multiplatform mobile apps)
- Unity3d (multiplatform games)
- Monogame (multiplatform games)
- Unreal Engine 4 (build system)
I guess Swift could fill the same gaps. I would especially love to be able to develop multiplatform mobile apps with swift since switching between ObjC and Java all the time is quite taxing.