Since polls are worthless, best to look at history. You know, the stuff you are ignoring.
Just so you know, I don't agree that your stretched reading of "history" gives a rational reason to think Giuliani would lose to Hillary in 2008.
For one thing, you have to pretend that Bush was the "conservative" candidate in 2000, to fit your supposed pattern. But if you were around FR back then you might recall that this is far from the truth: actually, Bush was the "electable" candidate and considered too wishy-washy (remember "compassionate conservatism"?), and tons of Freepers were griping and grumbling (just exactly as you are now) that we should instead nominate a real conservative (with no chance in h*** of winning) like Alan Keyes or Bob Smith. (Remember?) Bush's defenders (of which I was one!) were accused of "holding their nose" and pushing "partial socialism", and dire predictions were made that it would split the party, and all that.
How'd the 2000 election turn out by the way?
In other words, George W. Bush was the 2000 version of Giuliani, not the 2000 version of, oh, Duncan Hunter or whoever. Sounds like you're the one who's forgotten history.