Eurogamer has an enjoyable, relatively compact "forensic" detailing just why the Sega Dreamcast, a console years ahead of its time, failed. They argue that it wasn't Sony who defeated Sega; it was Sega.
By November 1998, when the Dreamcast first arrived in Japanese shops, it had been ten long years since the popular Megadrive, a decade punctuated by a triple whammy of high-profile hardware mistakes...the Dreamcast simply came too late in SEGA's hardware decline to reverse a long-running downward trend. For all its technological innovations and excellent games, SEGA's misadventures during the 1990s had left both gamers and publishers wary of any new platform bearing its name...Even if it had shipped with a champagne fountain and a nozzle that fired a constant stream of chocolate and diamonds into the player's lap, it seems likely that many potential owners would still have adopted a "wait and see" attitude.
While we gave away the article's thesis, it's still worth heading over to the link and giving the entire cathartic piece a read (before polishing off a sixer in DC's name and loading up some Shenmue. [Eurogamer via Kotaku]