I've no real clue why F# was productized, but I'd like to think it was because MS realized it has to stay competitive. F# is probably the most advanced language with that level of tooling, support, libraries, etc. I know F# is the only reason I continue to target the CLR. At the same time, MS's F# support certainly feels like it's just lip service, even while their flagship language lacks basics like a REPL. (I know, Roslyn will cure all.) I've yet to see any marketing suggesting F# would be a better choice for many projects; only esoteric sciencey and maths usages see suggested.
What'd really be forward would be for MS to support Rust or a project like that. (I believe they hired the guy behind BitC but I don't think it was for language design.)
According to Don Syme's blog posts, certain "product team members" said that "generics is for academics only." However, he did not name Anders Hejlsberg as being one of them.
Here's the blog post: http://blogs.msdn.com/b/dsyme/archive/2011/03/15/10141602.as...
Also see: http://blogs.msdn.com/b/dsyme/archive/2012/07/05/more-c-net-...
Also see the story from the other side: http://blogs.msdn.com/b/scottwil/archive/2007/10/24/working-...
I wonder if MSR's implementation of generics in .NET 2.0 was why F# got bundled into Visual Studio as a first-class language. IronPython, IronRuby, etc. never got that type of internal buy-in and got spun-off instead.