>The appearance of risk is more important to most businesses than actual risk. Ruby isn't dominant, therefore it is perceived as risky ...
That's not quite right. Anecdotally, I've seen or read about big corps using hot JS front-end frameworks like Angular and Backbone, server frameworks and databases like Node.js, MongoDB and Redis, and programming languages like Python, Erlang and Scala in production. Even if you look at the big tech corps (such as Yahoo, Google, Twitter, Facebook, Amazon), internally there isn't a whole lot of Ruby either. The big poster-child for Ruby, Twitter, is now most known for migrating away from Ruby than for actually using it.
I'm not a Ruby guy, but it doesn't seem like cliche corporate conservatism is what's holding Ruby back. It looks like it's Ruby, and specifically the Ruby platform. Maybe pretty Ruby language semantics aren't enough to make up for Ruby platform downsides. Maybe there just isn't a good reason to use Ruby.
>Java's complexity might actually threaten the survival of a small project
The choice of Java would not threaten the survival of any small project. Though Java is (still) not a very pretty language, the tooling around it has gotten enormously better from where we were in, say, 2003. Current frameworks like JEE, Spring and Play are actually pretty great to work with.