This is definitely true in the US and Canada. When compared to skiing and snowboarding over here, skiboarding is tiny spec in the snowsports industry.
In Japan, Russia, and some parts of Europe, though, there is actually a more significant industry that is currently growing. There have been Skiboarding comps with competitors from across the world in Dubai, Latvia, and Romania in the past few years. There are a handful of rather successful core companies (Revel8, Allz) that sponsor a good amount of talented and dedicated riders. While I have to admit they are not at the level of top pros in skiing and snowboarding, and definitely do not get paid a salary, guys like Dave Lynam, and Borja Fernandez are putting down some impressive shit on skiboards. Also, with a lot of recent exposure in Be-Mag, the biggest freestyle rolling publication out there, the sport has the potential to grow more in the future.
No, I am not trying to say that skiboarding is or will ever come close to being as popular or as big of an industry as skiing or snowboarding. But, I wouldn't go as far as to say that it is completely dead either.
Time to get weird.