With the PSP and PS3 I was (mainly) thinking that the similar approach of the PSP and PS3 may have worked better for the PSP because consumers had already seen value in the extra features it added; and (somewhat) similar products, like the iPod and PDAs, with similar features already sold for a similar price. The PS3 stands alone in terms of price, and few people have products with similar features so they may not see value in them.
The Wii and DS differences could be caused because the Nintendo DS made the approach much more trusted to both gamers and third party publishers; it could be argued that the Wii had far more games early on because of the success of the Nintendo DS, and many gamers were willing to buy Wii systems because of how much they enjoyed the Nintendo DS.
