I would speculate that anyone doing any real work in Ruby doesn't wait on the distro to provide it. I don't do that with Perl, I compile my own. I would imagine Rubyists are the same way too. Anyway, kudos to the Ruby folks.
Off-topic, but have you tried Gugod's Perlbrew for handling multiple Perl interpreters? It's like rvm, but for Perl. I've been using it for a bit with great results.
When I tried it (earlier this year), it wasn't quite like RVM. RVM is very versatile, powerful and polished. Perlbrew is getting there, but seems good only for particular limited ranges of use. Things I got used to with RVM weren't ready yet in Perlbrew. Various Perl versions wouldn't compile for me successfully. You can also compare the Synopsis of Perlbrew with the range of rvm commands and switches to get a feel for how much is missing in Perlbrew. I really wish Perlbrew gave me a good out-of-the-box experience, because it would be very handy for me, but that wasn't the case.
