Yes, Apple provide X11 with OS X. But you’re not supposed to use it. It’s not for lazy retards to base their Mac platform strategy on, it’s for desperate people who absolutely must use that X11 app that some scientist wrote back in 1993.
I find mathwork’s attitude a bit whiny. On moving away from X11: “this is a multi-year endeavor”. Well, yeah. I’m sure it is. But OS X has been out for over 8 years now!
Bottom line: if your answer to “do you have a Mac product” is “Yes, we use X11″, then you do not have a Mac product. You have an inexcusable pile of dingo turd. If the answer is “Yes, it’s written in Java” then you just upgraded your turd to offal. Congratulations.
Of course, this is just my opinion. My opinion and the opinion of every other Mac user. If we liked using X11, we’d all be using Linux already.
PS: Firefox gets it right. How hard can it be?