"Yes, I've probably heard of your obscure fast-as-C language that has a great web stack... to a first approximation, nobody else has."

It's less obscure than Rust and among web developers less than Go as well. How is it obscure, really?

http://www.indeed.com/jobtrends?q=scala%2C+rust%2C+Clojure%2...

That's nonsense. Scala is pretty well known. (Apache Spark, Play Framework, Spray, Akka, Scalding, Kafka, etc...)

As for the web stack: Play, Scalatra, Spray, etc... It can also use the fairly mature Java libs as well: Jersey, Jetty, etc...

On the other hand, I don't know of any popular projects that are written in Rust, other than what Mozilla is doing with Servo.

I can name companies as well: Twitter, Airbnb, LinkedIn, Gilt, Foursquare, The Guardian, etc...

Github still probably runs mostly on Ruby as well, and for performance, you could use JRuby.

Scala is far from obscure