Who holds the power in today's IT world? The guys with the budget? The testers? The developers?
I would say that the operations department has lots of power in many big companies. The operations department sets the scene and it's relatively concrete and rarely changed... Introducing new things to the operations environment isn't done without lots of calendar time passing and lots of friction along the way. You, as a developer, must have very good reasons indeed to want to take on the task of trying to bring about a change in the operations environment.
I believe this situation, regarding where the power is nowadays, is a very strong reason for the potential success of JRuby (and IronRuby as well). I'm thinking about the possibilities that JRuby brings for the developers, without causing problems with the operations department. I mean that even if the operations department is strictly orthodox when it comes to introducing new runtimes in the operations environment, you can now write apps in Ruby and execute them on the plain old Java runtime (POJR?) that the operations department has probably already decided to support.