It lives but it's not exactly thriving. OpenIndiana struggled, OmniOS gave up (and got picked up again) but still all that struggle makes me expect that Illumos will eventually fade out. At the latest when/if Joyent goes out of business. It's a shame because I like SmartOS a lot but it nowhere has the momentum Linux has. I don't see who will write all the device drivers for the next generation of hardware coming out.