If OPs concern is only availability of cheap talent, there are only two choices: nodeJS and python. Which is what most code academies, the main source of cheap ready-to-grind talent comes from.
Ruby used to dominate this space; in fact, I think the whole online code academy surge was lead by rails, although someone more in the know might point out I'm wrong. But market forces have changed the situation and favour nodeJS and python. For some reasons. Both are easy to setup, easy to learn, interpreted, with an integrated REPL setup, integrated packaged management. Just like Ruby. Where they differ? They dominate a valuable niche.
* JS owns browsers, and that strength creates other potential value points, starting from "what if I can use the same code in server and client" all the way to "what if I can use the same code for web and native".
* python owns ML, probably the most on-demand niche in the market now. It has the most complete ecosystem of ML libraries even your mother can use (R was competing until 3 years ago, I don't think it's close at this point). This opens up a lot of possibilities, such as "what if I can deploy my ML model along with my web service", or "what if I can use the ORM layer that I use for the web directly to feed data directly to my data analytics toolchain".
These questions make CTOs and Eng Managers everywhere very excited, as the thing they hate the most is "technology drift", i.e. betting on tech which eventually loses community mindshare and inevitably rots to the point it gets rewritten in PHP.
I love Ruby, but it doesn't own a niche. It's particularly strong in the web application space, mostly due to Rails, but so is PHP, so is Java, .Net, and probably even VisualBasic. It's not backed by any megacorp, so it can't even claim that fake sense of validation entitlement Google's go has.
Developers love it, and it has a lot of value and success stories going for it, specially considering how 80% of Y-Combinator most valuable companies are built on it. So it'll never disappear, and someone's always going to bet on it. But it'll never be 2011 again, so expectations of cheap labour have to be aligned with that.
Choose ruby because you like ruby. Choose ruby because you feel a creative release with it. Choose ruby because it's not just about delivering customer value, but having fun cranking out features that look fun, and your users might think so too. Github wasn't the first CVS server with a UI, but it became Open Source's social network because they used ruby.
And goddamn it, make more ruby libraries. Eat some of those niches. Make some ruby ML. Compile ruby to webassembly. Add value to ruby. If you add it, they will come.
