I wonder if the name is actually a part of the problem? It's been 10 years (more or less) and to a first approximation, Illumos has got zero value as a name.
Some of that might be due to its murky origins, with OpenSolaris, OpenIndiana, Nexenta, SmartOS, OmniOS, etc, all having an unclear relationship and basically muddying the mindspace that Illumos sought (and seeks) to occupy.
It's probably too late, but a rebranding exercise might help clarify that it's the survivor, and could also highlight the technical advances it offers, both over Solaris 10 (which is the last release most people used) and Linux (which is what it's competing with).
Some of that might be due to its murky origins, with OpenSolaris, OpenIndiana, Nexenta, SmartOS, OmniOS, etc, all having an unclear relationship and basically muddying the mindspace that Illumos sought (and seeks) to occupy.
It's probably too late, but a rebranding exercise might help clarify that it's the survivor, and could also highlight the technical advances it offers, both over Solaris 10 (which is the last release most people used) and Linux (which is what it's competing with).