Depends if the Super Wii releases this Year or next Year really...
If it releases this Year and has specs that are similar to the PS3/360, I feel that the PS3/360 could possibly keep going for another 2 (3 Max) Years without a successor.
If so, then we could see America and EMEAA fall... But I doubt the PS3 will catch the Wii in Japan, the lead is too much there and without big games like Dragon Quest/Monster Hunter the PS3 just wont reach the Wii's potential 12 Million plus. At least, IMO anyway...