The only point in time in which a mascot was close to outselling mario was in the PS1 era, and that was crash bandicoot, we can see where he is now.

And no, no single character in gaming can become bigger than Mario.

Many have tried...Many have failed

Next to 8.39, 9.21 and 20.76 million units sold to consumers, 3 million doesn't seem like much.

@OP no and they don't need to.  The Platforming genre is limited to strong selling veterans and weak selling newcomers.  There's no long investment to make.  Trying to destroy Mario with a new I.P., at this point, is like trying to destroy an army with a peashooter.

It's an interesting question. Not whether it would kill Mario or not, but whether MS or Sony will look at NSMB:Wii sales and think "hey, our consoles could do that too, couldn't they?".

They didn't seem to respond to Mario Kart Wii though, but that's somewhat more dependent on the Wii remote. Maybe they will.

Nothing will ever kill Mario in sales.

Quality, well... That's another thing.

you tend to ask very naive questions:
will ps3 outsell wii?
will there be a mario killer?

those are question that should not be asked anymore during this so called generation, not to offend PS3 fans, or to gloat. but those 2 questions have been answered for the next 5-10 years, and the answer is no,
the PS3 or 360 have no chance in catching up. there was an article explaining that even with drastic slowdown on the wii part
it was still imposible to catch it ( i couldn't find but i'm sure some one in here has a link to it ),

in terms of a mario killer, add up all the sales of mario games for this generation, and compare it to anything on the ps3 or the 360.
the only one that gives mario a fight is halo

Sony had the chance with LBP but they failed.

What are you implying..

This

Mario is legendary...I don't think any game could become more successful...