At the federal level I think the care is chiefly about re-election. At the state level I see a mix of people who are involved out of a sense of civic duty, and people who have designs on moving up and acquiring more power.

If politicians represented fewer constituents I think they'd be forced to care more about their constituents, if only because each individual voter wields more power. I certainly think that I have more power to influence my local politicians than I do my state representatives (let alone my federal representatives). My local politicians also live more proximate to me, and share more in the physical problems of the region. My US Senators live in my state, and that's about all they have in common with me.

This is what we get as a society when we aren't collectively involved. Why should our politicians care when we don't? How many of your neighbors have done the work to change politicians' votes or to raise their own politicians up?

I agree with you, but I also think there are many disparate problems we can point at. Ultimately, it all boil down to - we get the results of our efforts.