We don't hire people based on our tech stack, or at least knowing every part of is not a prerequisite. I know that great engineers can learn any stack quickly. If you have experience in writing similar (in this case frontend heavy JS) apps with any stack you can potentially work for us.
Anyways, the stack is part of your app. You can either write it yourself or build on existing components. Sure you can build your stack on top of more traditional technology, and likely there will be more potential candidates but finding good developers will be just as hard.
Our company hires people who are simply interesting, intelligent, and willing to learn.
We seriously consider non-coders for positions that will be primarily coding if they have a strong background in some interesting field (like statistics).
Not all companies are just vomiting lists of reqs into the void while sitting on their hands for the perfect candidate to roll in.
I've always been under the impression that those "50 years of Java + .Net + COBOL" adverts are purposely made unattainable because they already have someone lined up for the job, but they need to 'advertise' the job for legal reasons.
