My kids used to go to a wonderful little private school. It was a stretch to afford it, but I felt the benefits outweighed the burden. Then the tuition went up, and up, and up. So we left. The wonderful little private school is now precisely like all the other private schools in our area, in that it has two classes of students: rich kids and kids on financial aid. (We joke that the students are made up of the kids of the investment bankers and the kids of their chauffeurs.) The middle income families have gone into the public schools.
The political scene has seen the same shift. One hundred years ago, Republicans were rich and Democrats were not. That started changing with the Roosevelt Democrats. The change is now complete. As John at Power Line points out in a post about Democratic efforts to shut down Republican 527s:
Most rich people who care about politics are on the Left, and the Democrats have also mastered internet fundraising better than the Republicans. As a result, it is a given, for the foreseeable future, that in every important race the Democrats will have more money than the Republicans.
Just as the private schools in my community are for rich kids and their subsidized school mates, so too is the Democratic party for the very, very rich and their downtrodden buddies in select urban areas. The middle income families (and those shading high and shading low in that middle, too), have gone to the Republicans or, sadly, collapsed into complete political inertia.
The question remaining is whether, just as more money in the home buys the better quality private schools, more money in the political arena will guarantee the rich party a numerical advantage at the polls.