RVM is great. But by design it's a solution to compiling software on every machine. This simply doesn't work for lots of sysadmins, especially with lots of machines - it means installing a complete build environment which opens up much more evil.
Well, yes. And that's the effective situation we've got at the moment.
What I'm proposing is a full acknowledgement of that: if you want to live on the bleeding edge, then that should be supported as well as possible, but a very clear delineation should be drawn between the responsibilities of the distribution and those of the developer/sysadmin. RVM does that very cleanly, even if you only use it with the system ruby.