> By which you mean C# gets new features every year, and F# gets thrown enough tidbits to keep it looking alive?
Every new C# version makes interoperability more of a pain. The C# team have no interest in compatibility with F# and will NIH stuff that could've been taken from F# libraries. One of the biggest pain points for interop is tasks, for which there are half a dozen libraries for F# and everyone uses a different one. There's been an open issue for F# to have native task support for years, but progress is slow.
For all it's other features, I'm really not sure I'd call .net fast. It's got half decent speed, but it's not "woah that's fast"
> - C# and F# are constantly updated in coherently
By which you mean C# gets new features every year, and F# gets thrown enough tidbits to keep it looking alive?