Rails powers nearly 15 percent of the US e-commerce. I love it. Any time I have to use another framework it feels like a huge downgrade. Rails has so many things that make it nice to use
It's terribly painful to go and have to import everything you want to use when you want to use the Elixir console. That alone makes it not worth it to me.
You can find specialized roles than Rails and usually more experienced (understandably) but most companies would be really open if you told them you have a Rails background but want to learn Elixir.
The pool size is less, but the pay is more (depending on your demographics, experience, etc) in my personal experience.
But, honestly I chose it not for the market, it's just a better programming language to build stuff, period.