I've done legacy work in both and I'd never choose Ruby over C#. It might be a little faster to write the code the first time around, but maintaining a big legacy project stinks.
Also, none of Atwood's reasons is "I don't like working in C#." And several of the concerns in this post are obsolete.
Well who cares about that, really. I'm not talking about how pretty the code is; I'm talking about the ease of maintaining it. Ruby code frequently requires digging through the method and methods it calls to figure out the expected input.
But perhaps not without some pain for those involved making it: https://blog.codinghorror.com/why-ruby/