Didn't they sell megatonnes of wii's in there first few years of release? Maybe they just saturated the market in a short period of time. For those couple of years they vastly outsold the 360 and ps3.
The problem. It's a crappy console. The put the wii out after the 360 and it only had the power of the xbox1. It sucks for video games. So Nintendo has the opposite business model of microsoft and sony. They make all the money of hardware and not much from software.
With all those consoles out there they should be making hand over first on video games.
I think they'll be hurting when the next gen comes out. The Wii-U will only be marginally better then the 360/PS3. MS/Sony will put out really good consoles.
The casual gamer market the wii appealed to isn't too likely to upgrade. I think thats what happens when your console doesn't appeal to the hardcore gamers who actually buy games.