Well F# is based on OCaml, and it have been recognized for some time that C# is adopting more and more features from F#. As the article alludes to, this is not without controversy. Some feel that C# is becoming too bloated, and if you want to program in a functional style, you could just use F# in the first place. C# is much more widespread though, so this makes functional idioms more broadly available.
On the other hand, C# have also gotten deeper support for pass-by-reference and stack allocation which I consider more low level features. So I don't think the development is purely in functional direction.