Online games built with multiplayer is fairly important nowadays but if the game isn't multiplayer, there's no reason to think it needs online.
A good example of this is Gears of War and Metroid Prime 3. I'm (assuming) both are great games and both are great for different reasons. Gears of War has a fantastic online experience and without it the game would not have been a success. It would have shown what UE3 can do, but the single player isn't enough to keep players satisfied. With MP3, it doesn't need online multiplayer to make it a good game because it's not a game that was built with that in mind.
As for putting XBox, PS2, and GC games on that list, what's the point? Why don't you go ahead and add the NES, SNES, Genesis, and every other console on there. OMG! THESE SYSTEMS HAD NO ONLINE!! IT'S NOT NEEDED!!!! I know you're trying to say that games still sold well before online took hold, but adding that in is as silly as saying everyone game before HD graphics sucked because they weren't pretty.
As for Super Smash Bros Brawl, I think it needs online multiplayer. It could do fine without it, but it would be stupid not to have it. For multiplayer games, people do want to play online, that's simply how things are today. SSBB is a multiplayer game and people are going to want to play it online because the Wii is an online system (or so we're told).
