Well, you get two points with the PS2 replace rate and the third party support (PSOne to PS2 was a WINNER to WINNER succesor, GC to Wii was a LOSER to WINNER) because they were not expecting the Wii to be so successful.
But I really doubt Nintendo kills the beast early on its lifetime. Also, consider that Nintendo has yet to reach a sub-$200 price point, which they can reach... well... anytime they want. Right now, Wii's sale rate is higher than PS2's best days, that's why I consider it capable of beating it :)
About the competition... that's a highly subjective matter. I consider that the PS2 had a great competition last gen, but I don't know what you are referring exactly.