I agree with you wrt hiring but I think the choice on language (especially at startups) largely comes down to founder knowledge. As a full-time Scala developer

I agree with you wrt hiring but I think the choice on language (especially at startups) largely comes down to founder knowledge. As a full-time Scala developer (and long time Java guy) I've seen first-hand the benefits and drawbacks of both worlds: The highly populated world of Java libs and developers vs. the relatively niche Scala (but growing FAST!) community (relative to Java/Node.js/etc). The learning curve on Scala (just like haskell) is quite high for most "standard" developers. However even given that we usually don't have much trouble getting people on-boarded and productive in Scala. Java & Scala (thanks to the JVM) offer fantastic options for resource util. You can build very lightweight stateless microservices that run on a box with 1 or 2 cores. You can also build services that utilize hundreds of cores and terrabytes of RAM