Yes.Its a fad.
It could last many years and win the generation.
But next generation would be the wiimote + better graphics ,sound ,IA,storage etc.
So the technological progress would follow its pre-Wii path leaving the Wii ideas (innovative control + not so great graphics and sound) as a fad.
I am not sure if people are really liking the Wii.Most people I know with the console play Wii Sports ,some other are buying it for Wii Fit to get fit (poor people if only they knew) and some other to their children to play "safe child games" without violence(if only they knew about Mad World ,RE4 ,Manhunt 2 they would sell it as soon as possible) because the perceived child-friendly image.All of these buy the machine ,play the Wii Sports and maybe Wii Fit ,get several Wii Plays to have more controllers ,maybe they get one more game ....and then it starts collecting dust.
But there are so many unaware customers in that blue ocean Nintendo has found that it can keep selling hardware like mad for enough time to win the war.