According to the Pew survey, Democratic registration has increased since dipping in the aftermath of 9/11. The results (released this June) show a 33-28 Dem advantage nationwide. When leaners are included, the Dem advantage is 47-41%.
The GOP has been waging a 20-plus year war on labor in the US. The Bush administration is simply the most recent, and undeniably the most ruthless about it. See Robert Borosage's story in the American Prospect, for an overview.
The war on labor is one front in the effort to shift power, resources, and benefits from earners to owners.
I agree, we forget that the post-war prosperity was built on giving working Americans a fair shake.