Why Aren't Companies Hiring for the Cool New Technologies?

I would gladly hire someone who's done a lot of Ruby on Rails to work in node assuming they don't have like an allergic reaction to JavaScript. If you can prove you just have really solid technical skills and especially applied to business problems, then the technology doesn't matter as much. I look at Elm right now is pretty getting pretty high up there on the hype cycle. So they're explicitly hiring for ability to learn Elm, not expertise in Elm already. And I think that's true for a lot of other really new technologies.