Until we start seeing ports of leading edge multi platform games on the Wii, the consoles are not in the same class. The fact that we haven't seen any high profile HD games announced for the Wii does not refute this.
Why no DMCIV port from Capcom, one of the biggest supporters of the Wii platform? We still have people hoping and petitioning for RE5, but still no announcements from Capcom. No Assassin's Creed, no GTAIV, no CoD4, Oblivion, UTIII, the list goes on forever of games that will appear on both the PS3 and 360, but not the Wii. Is it because there's no market for these games on the Wii? Or is it because restrictions of the hardware would simply require too much downscaling by developers to produce a port that is not the same experience as the original?
Now if you find yourself in the position where none of the big multi-platform games are something you're interested in playing, then you are clearly in the Nintendo demographic.
Third party support should continue to improve on the Wii. With any luck, it won't be on the basis of volume, but quality. In a best case scenario, we will see more third party exclusives on the platform that cater to the Nintendo demographic while making full use of the platform's hardware, namely the control scheme. Will they be the most impressive games in the industry? No, but it's not important so long as the games are engaging and ultimately FUN to play.
As it stands, the best games for the Wii for the vast majority of Wii owners are by Nintendo. Games that we will never see on the PS3 or 360. Games that are the best, if not the only reason to own a Wii. Anyone interested in playing them isn't going to make absurd comparisons between Mario and GTA or Mario Kart and Gran Turismo as to why they don't need a Wii, they'll just buy one anyway to supplement their gaming wants.
If all we're looking at in terms of market relevance is straight sales figures, then an automotive analogy would be to say that Ford and GM are both beating automakers such as BMW and Mercedes in a direct comparison. Of course, most recognize they cater to different consumers with different earning and spending habits, as well as what they expect to receive for that premium.
But Ford and GM both sell significantly more cars that either BMW or Benz, so that still puts them on top in the overall automotive market, right? Ultimately, you get what you pay for. And for the majority of auto buyers, a Ford or a GM does everything the owner needs, at a price most anyone can afford. But having a car that sells more does not make it better or even equal.
Sales aren't the final word. Equal sales don't mean competing on even ground. Greater sales don't mean competing on a higher level. And high sales numbers don't magically make the hardware anything greater than what it was originally engineered to be.
So long as any hardware platform remains profitable, whether due to reduction in manufacturing costs or due to soft licensing fees, and continues to see growth over the previous year, that's all that matters to the companies producing them. Anything beyond that is boasting rights, which Nintendo has certainly earned after a long absence from the top spot.