I think this metric is invalid, the market rarely takes what's best, but rather what's trendy.
Before you begin to troll me, what I'm saying is that >>the metric is not valid<<, not that one language is better than the other.
One thing I've learned is that your language/framework is an HR decision.
The jobs metric tells me that if you hope to hire >>experienced<< Ruby programmers, you can probably expect to have fewer to choose from, possibly wait longer, fight harder, and pay more to get them.
I'm not saying you can't hire good programmers and give them a few months to transition, but that wouldn't work for my bootstrapped startup that's planning to ship product in 90 days.
You might say, yeah, but with 2k Java jobs, you have to compete against a lot of employers. Personally, I'd rather take my chances with a deeper pool of Java talent that I can out recruit the competition.
Even within the Ruby jobs, the majority have a Java requirement within them as well.
Been hearing Ruby aficionados for like a decade, but sorry, it just hasn't penetrated.