If the Wii is competing with the PS2 right now then the PS2 is getting it's ass kicked and Sony need to come up with something that can compete with the Wii.
By extension Nintendo don't need to come up with something to compete with the PS3 and 360 because they are already making boatloads of money on their 'last generation' product and need not take the financial risk of entering the HD war.
The "Sony is the technology leader and feels compelled to be on the technological edge" arguement is redundant because is merely their way of trying to make money, they aren't doing it due to some personal moral imperative to provide us with the best technology. Furthermore in that regard they fail when compared with PC's.
The technology that moves us forward and becomes an integral part of our future lives is determined by the consumer, not the manufacturer and at the moment consumers are suggesting that altered user interfaces are the way forward, not raw processing. If Wii continues to be successful this generation and then brings improved motion control into the next generation, Sony and Microsoft risk being the ones who appear, in the eyes of the consumer, a generation behind.







