There are several causes for this drop in median income (and the fact that more than half of the population now lives on less than $50,000). Some of these factors are -- the loss of millions of jobs due to the Bush recession, the extremely low minimum wage (with less buying power than the minimum wage in the late 1960's), and the stagnation of worker wages (thanks to the weakening of unions, making them less able to bargain for a fair portion of the increase in productivity).
This brings up a serious question. How much income is required for a household to "get by" these days (i.e., having a minimally decent standard of living)? A recent Gallup Poll decided to find out what Americans thought was the income needed to "get by" in their communities (the survey being conducted between April 11th and 14th of a randomly chosen nationwide sample of 1,012 adults -- with a margin of error of 4 points).
It turns out that 57% of the general public believes that more than $50,000 is required to maintain a minimally decent standard of living these days -- and the mean average of all respondents was that $58,000 was needed. About 29% of respondents said households could get by on less than $50,000 (and 7% thought a household could get by making less than $30,000). This means more than half of all American households are trying to sustain themselves on less income than a significant majority of Americans believe is necessary. Here is a demographic breakdown of the average income believed needed (by income level, region, and community type):
If that doesn't make it more than obvious to you that the Republicans don't care about anyone but the rich, then you are not living in the real world. It is time for our government to act to help ordinary citizens to have a better life -- and the only way for that to happen is to vote the GOP out of power. Failure to do this will just cause the median wage to fall even further, and make a lot more Americans have to live on an insufficient income (as the middle class continues to shrink).