I'm sure it will last a good 5 years.
but the system does need more (or better) third party support. . . but thats not Nintendo's fault. . . the developers should stop being so greedy making crappy games that don't cost much to produce.
If there is a console you should worry about it should be the ps3. . . the games simply take to long and too much money to develop. Though it obviously has the highest potential.