> .. you can write vastly more complicated programs that are, say, 80% as fast as hand-optimized C for only 10% of the effort of hand-optimized C.
Computer Language Benchmarks of GHC versus C don't seem to be close to matching your 80% as fast claim [1]. Also, the 10% of the effort of hand-optimized C bit - seem to recall there was a caveat - "if you happen to Don Stewart" [2].
The following is just my vague, uninformed impression, but Haskell and Go seem to be opposite ends of a spectrum, with Rust somewhere in between:
Haskell: good for expert individuals and small teams. The language is highly sophisticated and the compiler is rather slow. At heart, it's a research language, so the direction might not always suit production use. If you contract out to a Haskell development shop, who do you turn to with your Haskell code-base if things don't work out?
Go: designed by Google for their use-case - large teams of commodity programmers. It's very quick to onboard programmers - they can be productive and non-dangerous quickly. The language is very simple and the compiler is very quick - which is again good for scaling large teams.
[1] https://benchmarksgame.alioth.debian.org/u64q/compare.php?la...
[2] https://donsbot.wordpress.com/2008/05/06/write-haskell-as-fa...