his second paragraph is good, but his first is off. graphics aren't the end-all, be-all. those people are idiots. graphics are a factor, however, now that all the consoles are competitively priced. the wii also sucks at online, which has become a big part of gaming. before the m+ wiimote, controllers were just too expensive. to this day, i still only have 3 wiimotes, 2 m+, 2 nunchucks, and 1 classic. since the price of a wiimote and nunchuck is about equal to a wireless controller at full MSRP (which means it's easy to find the other controllers cheaper), the consumer is going to feel nickel and dimed.
then there's the main attraction. games. it's the games that are doing the wii in. how long do wii owners have to wait between AAA titles? 3 months? 6 months? the wii doesn't see a lot of great games making their way over. there's no christmas rush on must-have wii games. when people were buying halo: reach, CoD:BL, fallout:nv, dead rising 2, gran turismo 5,castlevania:LoS, and SUPER MEAT BOY last year, what were wii owners buying? goldeneye, and what else? the wii has the highest percentage of shovel-ware of any of the other consoles, and by a wide margin. multi-plats are rarely adopted to actually take advantage of the wii's abilities, and end up being terrible, or really really late like CoD4.
i own all three, and my 360 gets the most play without question. the ps3 will be getting more once i wrap up DA
and move on the uncharted series. i'll at least play the new zelda when it comes out, but I haven't turned on my wii to play a game outside of a party in a very long time. in fact, i haven't seriously played it since super mario galaxy. my pc will be getting more play than the wii, especially now that it can play newer games.
those are my reasons, although i'm not a person who usually rags on other consoles, since i'd be insulting my own purchase.