The "inconvenient truth", if you will, is that for a game to sell well, people actually have to go buy it. They actually have to want to go buy it. And while a lot of gamers play lip service to saying that "third party games on ____ Nintendo console should sell better", when looking at the numbers, it's fairly obvious that a fair majority of those same people do not themselves actually put their money where their mouth is, and go out buy even SOME of these games.
Some people do, but obviously, not nearly enough. And thus the conundrum. People don't really get a right to complain or argue about game sales, if they didn't even try that particular game themselves. If you don't go buy a game yourself, you really don't have much right complaining that other people don't go buy it either.
Ultimately, the only way third party games on Wii U are going to sell better, is if the people doing the complaining about their sales, actually go out and buy the games. Same with the console sales. The only thing that has ever driven sales, if people actually buying.