This craze for the most modern stuff -- and believing people can't pick it up -- drives me crazy.
I'm the hiring manager for a small (5 people) software engineering group. We use Scala. Nobody in my team used Scala before they joined the company -- they learned (hell, we use Scala because THEY decided they wanted to use Scala). One of these developers didn't even know Java before he joined the company -- he was a Perl guy, through and through. He's one of my best.
We're looking at a candidate now who actually retired from the workforce after being an architect for a while; her last time writing code was 15 years ago. We like her because she has a fantastic fundamental grasp on computer science principles and the passion to learn quickly -- we think. So we showed her the code base for one of our open source projects, asked her to implement a feature that had been requested, and let her loose. She came back with the first version Friday; we'll see how it goes.
Concurrency isn't Olympic Gymnastics where if you haven't been doing it from the time you were six years old and if you're older than 20 years old you have no chance. It's just something to learn. Smart people can learn pretty much anything you put in front of them.
Hire smart people.