yeah, and MS doesn't care that you are a gamer. They throw everything at the wall and see what sticks. Same thing with EA. These companies can afford to bleed money. For everything they do for you gamers, they also release/develop Sims Online, True Fantasy Live Online, buy companies like Rare who fail to perform, etc.
As for online itself, Nintendo's lacking of it would be important only if they didn't release other quality titles as well. You are a gamer right? So you should be into games, like Paper Mario, Mario Tennis, SSB, Mario Kart, Donkey Konga, Pikmin, Tales of Symphonia, Baiten Kaitos, Viewtiful Joe, RE4 and hundreds of other superb games released for Gamecube.
Many GAFers seems to still forget that online gaming isn't the future, it is just another type of game. Just because the Gamecube doesn't go online doesn't mean it doesn't have great games. Consoles for the past 25 years didn't go online before this generation (for the most part) and they still released tons of amazing games.
By not going online Nintendo certainly missed releasing certain types of games that today's gamer would have eaten up, but agian, it is just one type of game. There are plenty of other games out there that don't need to be online.