It seems like 'the issues' are being framed in ways that are convenient for the political parties. The Democratic and Republican parties each get about the same

It seems like 'the issues' are being framed in ways that are convenient for the political parties. The Democratic and Republican parties each get about the same support (plus or minus 5%) from various 'classes' (as defined by income or wealth quintiles), but get very different support from different ethnic groups (national origin, and not just race has a big impact). That said, I think your class-based paradigm is just as badly flawed.