Its really hard, but i wouldnt say its impossible, there are core gamers in the Wii the most obvious prove its Resident Evil 4, it was a remake it it sold over a million copies, the problem is most of developers dont take the Wii seriously the third party core games on the wii are just average games on the other consoles (Conduit, Madworld..) developers expect to get great sales with not so good games, adn there is the problem. As soon as they decide to make real good games, the core gamers will pop out and the sales will improve, and thus third partieswill start making better games. end of the story ._.
Nintendo is the best videogames company ever!