Hm... perhaps because they have thousands of paying corporate customers who started using Solaris before Linux even existed, and they needed to transition them to a newer/expensive hardware without affecting their Solaris-tuned software?
(just thinking out loud, can there be any other reason?)
Congrats on hitting "the one" then!
Loving your updated design, by the way. Here's a great example: http://www.couch.io/case-studies