How much have voters really change?

I'm not discounting the possibility of a major Democratic realignment, not at all.  But I feel compelled to point out that many of the people excited by massive voter shifts are confusing a) serious Bush hatred during a once-in-a-generation financial crisis and b) massive black voting turnout to vote for the first black president, a definitionally unrepeatable happening with c) actual permanent demographic change in the electorate.