I can only speak from my very limited context, which is "big banks, and payment processing". This won't dent that realm in the least, at least not anytime soon. The tech I'm using is 5-8 years old (J2EE, some even in Java 1.4 still), and the banks have no desire to move off of it.
A few "renegades" are using JBoss for some small one-offs, but nothing in their main processing stacks. With open source, there's no one to sue, no one to hold to the fire, and "only hippies write systems with it"(a paraphrase, obviously).
It crushes my soul. (But pays my mortgage.) I'm really conflicted as to my future, honestly.
Again, this is a very narrow view of a very limited scope, so I'd be anxious to hear other people's experience.