Recent electoral history shows that if there is a landslide in the making, it is evident much earlier in the contest than now. Clinton in '96, Reagan in '84, Nixon in '72, and Johnson in '64 all had clear and substantial leads for months in advance of the vote. The exceptions might be Reagan in '80, when he pulled away from Carter in the last week of the campaign, after his performance in the debates (and Carter's weak performances) convinced voters that "he was okay" for the job. Bush 41 took the lead after the GOP convention in '88, but held it through the Fall, so that race might be one other recent contest where the eventual winner won big but gained the lead late. I discount Clinton in '92 since 43% of the vote is hardly a landslide (even though is electoral margin was quite large).
So, bottom line, the historical trends seem to be against a Bush landslide at this point, unless things happen very, very rapidly on a somewhat unusual timescale. More likely a redux of 2000, or something close to it.
I agree, and have stated that the final result will be more like 320 EVs, with probably NM, IA, and MN or OR and possibly PA falling into Bush's lap. However, three weeks is a lifetime, and remember the DUI. Now, the DUI was a VERY Bush-specific issue, because it struck at his "anti-Clinton" persona of truthfulness and because GOP/evangelical voters don't take lying very well! OTOH, little would damage Kerry with his base. However, a "Surprise" could still turn off the Indies or move them to Bush---an attack, new threats, a major Kerry gaffe. In that case, a 1-2% swing can mean a swing of, say, 40-50 EVs, moving, say, NJ and ME or PA and MI and OR, or any combination of them, to Bush. So it's not out of the question.
However, generally speaking, you are not only right, but historically there have been very few blowouts. The elections of 1876, 1880, 1884, 1888, and 1892, for example, were VERY close and a few votes would have swung several states. Even in the Great Depression, when FDR was "invincible," the popular vote was quite close in a couple of elections.