Redhat is "open," (as in FOSS,) but it is not "interoperable."
Oh, it may be open source, and you can certainly fork the project, or tinker with any part of it you wish...but the various strands of Linux have diverged from one another quite a bit. The simple fact that the various distributions are package (and sometimes binary) incompatible makes things difficult unless the project is actively maintained or ported. (Or you are willing to toss gobs of time and money at it to do yourself.)
Redhat-based disties are Redhat based disties. Debian based is Debian based. Even simple things like vi behave differently between them. For all intents and purposes I consider the various distie "strands" as completely separate and non-interoperable operating systems. (Just as I consider Google's strand of Linux to be separate, distinct, and non-interoperable.) (I often compare it to NT-based Windows versus 9.X-based windows.)
Linux doesn't really talk all that well to anything that isn't Linux, (not the fault of the various projects underway to solve this...but the proprietary companies constantly release a new standard, then document it badly.) Lack of interoperability with proprietary platforms (regardless of who is to blame for that) further isolates Linux from everything else, making it just as much of a self-contained silo as the proprietary stacks.
I understand that if I have committed to JBoss, or KVM, I can take my information in those apps and move it to another distro. With enough tweaking, maybe it could be made to work on a SuSE stack or a Debian stack…but this still requires a massive outlay of testing and certification time. Time is money, especially in corporate IT. Do all the dependency programs and libraries exist? Have they been ported to the appropriate platform? Are there behavioural discrepancies in file system or file handling, etc? Even *if* I can get my app running on two separate disties, there is a whole other round of testing to ensure it runs in the same fashion. (For an example, see vi’s behavioural differences on Debian disties versus Redhat disties.)
Linux isn’t free...at the enterprise level, (where things like JBoss and suchlike play,) you not only buy Enterprise licensing, you spend a lot of time and money testing and certifying. For all that effort, I still can’t make JBoss interoperate with anything from MS, Oracle Google etc. Even if I have the pleasure of (maybe) being able to port my app from one Linux distro to another...what interoperability does that actually buy you?
Please understand I am not bashing Linux in any way here. My statements above come from the fact that my job entails a lot of interoperability work. Getting the various strands of Linux to coexist, talk to Solaris, Windows, BSD and $deity only knows what else is a big part of my year. In my mind, open source or not...from any practical standpoint Linux distribution strands are isolated entities.