Never; the Mario character somehow appeals to everyone.

Unless there is a major change in the industry, no company will make a new character in an attempt to identify with everyone ever again. Too much attention is paid to certain niches.

It's possible, but if it were to happen I would guess it was due to a decline in the popularity of Mario more than a rise in new megaselling series.

Uhmmmm

whats an IP? lol

It is possible, very unlikely tho.

Yes. But not for some time.

I predict it will happen around 2060.

Sonic tried. What is great about Nintendo is they were able to jump all their franchises to 3d pretty well. Sonic died in the transition. Well, some contender would be Tetris, Bejweeled, Wii Sports Series (even though they will be only at Wii, duhhh), Nokia's Snake(at cell phone games its really big, since it was the only cell phone games for years).