Perhaps this just underscores that the Democrats are the Party of the wealthy elite and the welfare class, while the Republicans are the party of the upper middle, middle, and lower middle class - the worker bees of the country.
I find it fascinating that a row-house/working class/union neighborhood like Port Richmond, South Philly, or Mayfair is more Republican - even with a majority in many precincts - than Lower Merion. And yet we are the "party of the rich", while they represent the "workers".
Perhaps we will finally come a full circle to the 1890's-1920's period, when the Republicans claimed the allegiance of farmers, small business owners, and workers, while the Democrats had the organized ethnic grievance classes as their base. Even back then, we had the patronizing scene of the Democrats running Wall Street elitists like Cox and Roosevelt and calling the Republicans running ordinary Joe types like Harding and Coolidge the party of the rich.
It just reflects the fight over cultural issues. There was a different dynamic back then, with protectionism and racism and the detritus of the civil war in play. I suspect that this cultural conflict will fade in time, as compromises are found, however difficult. But probably the mean income gap between Bush and Kerry voters was smaller than in any election between a Republican and Democrat in history - ever (the South back then was dirt poor, which distorts the numbers admittedly), and maybe the median income gap as well, althought that is more iffy.