Who says? Third party support is VASTLY overrated IMO, especially when you have such a strong first party base like Nintendo. They are not the end all be all. In fact, if anything, too much third party control is very harmful to the industry.. The prior DRM policies of the Xbone (before MS came to their senses and corrected it), are a major example of that.
Wii has sold 100 million and still has a shot of outselling the PS1, made Nintendo a ton of money, and is complete with a plethora of fun and exciting games that appeal to many.. So at the end of the day, does length of console life really matter? Sure the PS2 was in a whole nother league altogether, but there are a number of factors in play, besides its huge library; including a near monopoly on third party support, a boon in the economy, people rebuying PS2s because of new models/breakdowns, and a patheticly weak showing from its competition.
I just love how creative you "hardcore" get in discrediting the Wii in any way possible. Makes me laugh..