ah, are you new? you must be. Let me clear this up for you.
The market in the NES era was something like 75 million NES consoles and 15 million master systems- at best. (the master system kept selling in brazil until 2009, skewing it's numbers).
nintendo controlled over 80% of the market, and in reality the numbers were probably higher since again- the master system's numbers are inflated a bit.
The market currently is 100 million Wii systems, 70 million PS3's, and 70 million Xboxes. Nintendo controls about 40% of the market- and the wii is basically dead. The ps3 (and presumably the 360) will continue to be supported for several years. We'll probably see that marketshare drop to 30-35% after it's all said and done.
nintendo isn't anywhere CLOSE to the market dominance they used to have. Most gamers do not own wiis.
edit:
and in case you think I'm nintendo bashing just to bash, I'm not. Market conditions were terrible. Third parties were limited in output per year, per studio. Nintendo was found guilty of price fixing consoles to keep prices artificially high. Third parties were strongarmed into exclusivity agreements to prevent games from being released on competing systems. Censorship was rampant, and content deemed offensive was removed at nintendo's orders on a regular basis. this could be blood, crosses, questionable language, dogs instead of rats, etc. The makers of maniac mansion had a VERY eye opening article on the entire process.
here it is.
i'm enjoyed my NES, but I'm not a fan of the way ninty did business back then.