see my reason above, its the main reason.
if Nintendo won the last two generations they would have the stronger brand name. Sadly, Nintendo never had a strong brand name. SEGA had an equally strong name before the PS1 came to market. After this generation Nintendo will finally truly have the strongest brand name. They just need to expand the market like the PS2 did.
You might want to ask someone who's been around those years, as you came into the world in 87-88 =) Nintendo by far dominated the market in popularity by the era of the SNES, when you were about 5 years old. By the tikme of the PS1, everything was attributed to Nintendo. It wasnt until the PS2 that people started using the Playstation name as the reference point for gaming. The popular opinion for Sony systems didnt occur until the mid/late 90s. Yet I can see from your perspective, thinking that its always been that way, as you were too young to recall the early days of console wars. =)