How come there's never been a 3D Mario game with co-op?

[CM30]

It's been promised twice in history, first with Mario 64 supposedly having Mario and Luigi being able to be used at once and then with Super Mario 64 DS meant to be featuring four player co-op:

Above: Remember that?

But with New Super Mario Bros Wii finally having some form of co-op in it, is it ever possible a 3D Mario game will have the same thing?

 

[TheUltimateKoopa]

There IS this you know:
http://www.youtube.com/watch?v=cvZFgeulx0k

 

[SuperMarioFanX100]

Because Nintendo doesn't want our money.

 

[Servbot]

I remember there were gonna release Super Mario 64 2 back in like 98. There was a single picture of mario and Luigi on a carpet. Some say it was a rumor, but it was in fact real. Nintendo scrapped it way early though. I forgot the reason but it was a good one(I know, but trust me, it was).

 

[Yoshi64Mario]

I hope so. Co-op would be great if done correctly (like a split-screen system that splits only when you move away from eachother). And none of that Co-Star crud neither. Controlling a Luma or a pointer is not the same as controlling a proper character such as Mario or Luigi.

 

[Steven9wii]

mario 3d land needs to have this in an update. so i think they will make one soon.

 

[Fillfall]

I think SSBB is the closest we're coming, with those almost 3D levels, but I hope for more..