Asthetically the cube looks "kiddie-like" and was poorly marketed. I believe these were two of the reasons the 'cube failed in europe.
If nintendo market the Revolution as aggressively as DS and broaden its appeal to all, then it should do ok, i hope.(Sorry, states the obvious i know)
Also Nintendo have learned a valuable lesson from xbox live i believe, and are now as we know going full-on with on-line gameplay. Something they themselves took no notice of when cube started its life.They have the support of sega for one. Can't be bad can it?
Also i Believe the ps3 will just be too expensive for too long for most people to afford. Coupled with difficult development tools and costs.(how many people and how long will it take to utilise blu-ray to its full potential? and how much will the public have to pay for the privelegde of owning a ps3 game? think about it.)
Just read on gamesradar.com that revolution will have a child-lock system that reads what rating a game is. Sounds like nintendo are gonna allow some rough software through whilst retaining a sense of responsibility allowing parents the choice over their kids gaming with this password system.
A nice marketing tool i guess.