"Those are not remotely good. Some examples closer to being good are Rust, a step in the right direction that’s still unfolding, and Haskell, a wonderful language hampered by a slow compiler and a lack of decent packages. (And probably several less popular languages, but popularity is an important factor…)"

Wait: so you are arguing that startups should use languages that are either incomplete (Rust) or that have slow compilers and poor library support (Haskell), or possibly some other "good" language that doesn't actually even exist?