Based on these figures: do NOT learn Ruby. Ruby is dead last in the "face-off", and looks like it would put you at a significant disadvantage compared to Java or Python.
That makes me wonder about two things:
1. Is Mixtent wrong?
2. Do companies really see Ruby on a resume and say "nope! next?"
No. Competent companies don't hire people for "Python" or "Ruby" per se. But the Ruby developer community is disproportionately well-stocked with web "programmers" who know enough Ruby + JQ + "SQL" (read: AR) to make good-looking, fairly functional websites.
It is easy to shoot these superficial programmers down, even from a cursory browse of a resume.
It's not that Ruby signals that you're a superficial programmer; it's that there are fewer superficial Python devs, and more superficial Ruby devs.
For the most part, your choices of programming language are a terrible way to differentiate or market yourself. You are far better off being clever about picking your application domain.
I don't like Python; I'm a Ruby developer (actually, I don't know why I stopped calling myself a C dev). But I'll freely admit: most Python programmers know Python because they spend their real day job programming.
I use rails a lot and I don't know much about the methodology used, but some of my non-rails coworkers have said that they view a lot of rails guys as prima donnas. The DHH "fuck you" slide and Zed Shaw's massive flameout probably contribute to that perception too.
Given that another big influence was ability to be a team-player then I can see how ruby guys are perceived lower on the list.
Your point #2 is not at all what this data implies. It shows that when presented with two LinkedIn profiles, users chose one developer over another. In that effort, Mixtent found a correlation showing that Python and Java developers were strongly favored in these comparisons.
Hiring decisions aren't typically made in the same way. If you have a Rails app, you need a Ruby developer. Granted, anyone can learn Rails, but I've worked with really talented people who were in the process of learning the Rails framework, and it's not something I'd like to pay for again.
I don't think they would say "Nope! next?" but there is a really good chance they would be using Python and not Ruby. But that shouldn't matter if that person is a programmer as language semantics can be learned by any decent programmer.
P.S. I have been a long-time Ruby user, and use it frequently for sysadmin/devops/proof-of-concept type stuff. I am not, however, a "Ruby guy" and would list it on my resume along with Python.
That makes me wonder about two things:
1. Is Mixtent wrong?
2. Do companies really see Ruby on a resume and say "nope! next?"