I think most polls put Christie's name recognition in the 70s. Rubio's is a bit lower. Walker's is pretty low. So there are plenty of potential GOP nominees with lower name recognition than Clinton has (she's well over 90%).
It's a lot more meaningful when you're testing two people with high name recognition (ex: Clinton vs. Romney) as opposed to say, a McCain vs. Obama poll in 2006.
Mondale was well known as the former vice president, but he started out at the beginning of 1984 roughly tied with Reagan. Reagan won by 18 points:
And Dole was well known in 1995 (being Senate Majority Leader, former presidential candidate, and former VP candidate). He actually led Bill Clinton in the polls in early 1995, despite eventually losing by ~8 points:
http://www.mail-archive.com/pen-l@galaxy.csuchico.edu/msg04399.htmlWhat is your evidence for this? I don't see how this hypothesis even makes sense. You could say that polarization will prevent a blowout from occurring, but why would it mean that the candidate who's leading polls right now would be more likely to win? And even if you can spin a scenario as to why, what is the evidence that this supposed phenomenon is real?
You need a baseline of presidential elections in which the early polls were predictive of the final result in order to prove such an assertion, but if you're saying that this only applies to very recent presidential elections in which both candidates were well known two years beforehand, then you have too few elections to work with in order for things to be statistically meaningful.