Now? Wii Sports or Wii Fit, I'd say. Even Smash Bros. has outsold every Zelda on a per-system basis outside Ocarina of time: Smash 64 (the weakest entry) outsold every Zelda game but Ocarina and Twilight Princess. 

Now, bringing the conversation back to you: in your example, do you see why Mario Kart was more profitable?

Halo outsells Smash bros too.  If we are talking about casual stuff then yeah i suppose wiifit did well but itll never do that well again most likely.  More of a one time thing.  Wii Sports is a game that comes with each console, not sold sperately.

No i dont see that.  Call of duty uses the same engine year after year and takes little resources with little time to make.  2 years to make each game.  Activisio-Blizzard has made a ton of money off of CoD.  All they have to do is pay a little for advertising but that is it.  This isnt even including how much DLC they sell.  I question your opinion because for some reason you think 33m makes more money thant 150m with DLC.

Yes, Microsoft's premier franchise outsells Nintendo's secondary "core" franchise. As for Wii Fit, it actually did it twice, if you recall, and Wii Sports Resort handily outsold the Halos/Call of Duty/GTAs/Gran Turismos of the world. But those facts are neither here nor there.

Going back to the main point, you're vastly underselling the resources and time each CoD game takes. As you say, each title takes two years to make: recall that before Infinity Ward went belly up the pattern was that IW made one game, then Treyarch (large, massive, huge-in-size Treyarch) made the other. And if you check the credits of each game, they go on for much longer than Mario Kart's credits do: simply put, they're man-intensive titles. Not as much as, say Assassin's Creed, but they still dwarf MK. It's been estimated that Modern Warfare 2 cost about $50 million to make, for example.

And lest we forget, each CoD game has the additional expense of being ported for at least three, often four different platforms. That's less expensive to do than making a game from scratch, but it's still a pretty significant expense: why do you think Wii U games aren't getting farted out by every third-party? Much, much more importantly, each Call of Duty receives its own nine-figure advertising campaign. And, unless you're the U.S. Treasury department, it's not "a little."

Each CoD receives its own, separate, nine-figure advertising campaign. Activision spent about $150 million on Modern Warfare 2's marketing, before the game launched. Do you reckon that Mario Kart's marketing was even $100 million? I mean, it might have been, I don't know. Buuuuut...I kinda doubt it.

So, to summarize: by your terms your six (6) Call of Duty games have outsold the one (1) Mario Kart game by a factor of about 4.5. Nintendo spent the smaller amount (one platform only!) to make Mario Kart exactly one time. Activision had to shell out development cash for six two-year games (total development time: twelve years), and they had to pay to port those games to 3-4 different platforms, each and every time. Nintendo had to budget Mario Kart advertising once. Activision spent more than three times the annual GDP of the nation of Tuvalu no fewer than six (6) times.

Now, let us be generous. Let us say that, in the end, the six Call of Duty games combined to bring in, say, three times the profit of Mario Kart (note: I suspect that's too generous, but c'est la vie). Activision, then, expended six times the resources, energy, and manpower that Nintendo did, while only getting triple the profit.

Do you begin to see what I'm getting at?