Stanley was also commissioned by the Michigan and national Demonratic parties to find out what went wrong in Macomb County, Michigan (auto worker suburb of Detroit) between 1964 when it was the most Democratic county of size in suburbs to 1984 when it became the most Republican county of size in suburbs. You can read all about it in his book Middle Class Dreams (1986).
In short: if Stanley Greenberg says Clinton by 7, Gore -7, Kerry -14, take it to the bank. Stanley knows what he is talking about and his wife will be one of the Demonrats who will have the hardest time moving rightward on social issues. He may be a left-winger (and certainly is to the nth degree) but he is paid big bucks to determine the truth and render it to his Demonratic clients. Nobody does it better on their side. His daughter Anna is now poised to supplement his efforts in life and succeed him when he is gone.
Finally, if you insist on believing the conventional figures you have posted, even they show 5% increase between Bush's showing against Gore and his majority showing against Kerry in those four years. Gore presumably did not do as well in the two-party vote as Clinton did against Dole and Bush the Elder. Don't look a gift horse in the mouth. There is substantial momentum either way and when you hear it from Stanley Greenberg in larger momentum, it is more meaningful than if it came from Gallup. Stanley is a LOT more cutting edge in his technologies. Also, don't forget that Kerry has modeled his political image on John F. Kennedy (not terribly well IMNSHO) and runs around fraudulently claiming Catholicism. If the GOP builds on what Dubya has begun, the Demonrats' funeral is in sight.
Well, I am not going to get into whose stats are better - the stats I cited are commonly accepted, the ones you cited are dubious. I'll stick with my stats.