A: Because this ad, and this console, never appeared outside Japan. Many people blame the Dreamcast for Sega's exit from the console market, but that's a harsh point for both the console and the company. Really, it was the Saturn that marked the beginning of the end.
The market share the Saturn ceded to Nintendo and Sony, and the money blown on developing such a complicated system, is what really put Sega on the ropes.
But oh, how things could have been different. This ad is so damn effective it's making me want to go out and buy a Saturn right now. If I'd seen it in 1995, in that hot shade of white (a model only ever released in Japan), I may well have lost my shit entirely.