The Dreamcast had so much potential, a year's head start over the PS2, a decent selection of launch titles, and online games, but I guess the damage was already done. They struggled to put their own franchises to good use on other systems since then, and now mostly seem to survive as a publisher and owner of a few third party developers.
In hindsight, perhaps it's more accurate to look at Sega as a company that had one good breakthrough with the Genesis that they could never replicate, rather than a once great company who failed. It was a long series of bad decisions after that, not just a single failure.
An interesting excerpt from the article:
"Just some of the developments coming to an Electronic Boutique near you: Truly interactive game movies starring hot Hollywood stars; immersive 3-D game environments using cheap VR technology; and motion-sensing technology that places you directly into the game"
Maybe they really were just ahead of their time, with the biggest companies still trying and failing in these areas. Or maybe it just shows they're just plain bad ideas.