Ah, you did not realize it was said at the end of last season - so now you have some context for Alonso's statement.
Wins, poles and championships are what define Senna, Prost, Micheal, Jim, Niki and others - how else would we gauge their greatness over time? Prost did not make Senna great, nor visa versa. Senna was great of his own accord - in his driving against the entire field, not just his results against a teammate. Alonso lost to Hamilton - a rookie - which certainly does not define him.
No more than Hamilton doing well beating Alonso and then losing out to Button. I can't understand the reasoning behind making that sort of judgment. I look at the manner in which Hamilton achieves, not how he managed against teammates. Which may explain why I was among the few defending him in 2011. But that's my point of view.
1. Fair enough, if the quotes were regurgitated, I assumed they were new.
2. Senna and Prost most certainy helped one another's legacies, despite taking titles off each other, with the proof being (which undermines your whole argument of number of wins etc defining a driver) that Schumacher is not universally accepted as being the greatest. He did the best during his career of hauling in the records which are likely never to be broken, but still most, and even Shumi himself, consider Senna the greatest, others say Clarke (2 WDCs !?!??!) and possibly Gilles (none!). There must be a reason for that, I wonder what that might be? I think it's short-sighted and obtuse to think drivers are simply defined by stats, which don't happen to take context into consideration, as obviously the drivers being mentioned have all proved themselves vs the rest of the field, we aren't discussing that, rather splitting hairs between the greats and what made them so. As for Lewis and Alonso, I firmly believe that they severely helped one another's reputations and legacies in the year they raced together, and it bears no influence that Lewis was a rookie. Had they not, Alonso would have raced against very obvious no.2 drivers almost his whole career till his Ferrari days, but that year of competing against Lewis helped consolidate his position as one of the best. The same is true but to a lesser extent for Lewis as he was up against Jenson who he beat (comfortably) 2 out 3 years against him and that was the only year he has been beaten by a teammate in F1, and he has been up against more WDCs than most (save for perhaps Ros/Mas of current crop I think?). Although truth be told I think there is a case of circular logic with Lewis and Alonso, each one thought of as a top driver because of the year they had vs each other, but it seems to be accepted generally that they are up there and their performances since seem to reflect that.
3. It seems you and I look at this very differently, which is fine because it is all subjective anyway. It depends on how you value certain factors, context, record vs teammate, the capabilities of a given car (Newey-made or otherwise 
) and what I like to call the 'wow factor', but ultimately it's a debate that will never be resolved, as opinions will always differ.
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