I think as a product it simply missed its window of opportunity.
It was never beefy enough to compete with pro products out there that relied on proprietary software integrating with specialized hardware - and when DV video really started to happen (thanks to Apple) FCP and iMovie were there to take over.
In the Windows market it still sits as a rather sophisticated prosumer product, but ultimately still has to compete with AVIDs consumer prodict and a half dozen others in the same space. We may yet see its death on Windows too.
If we see Illustrator cack, then you should worry...