Status Quo
I firmly believe that most people are either, pretty much O.K. with the way most things are, or so apathetic to the possibility of change that they don't care.
Of this great majority, there is no reason to stand up and demand that things stay pretty much the same. Who would bother getting out of the house to vote for someone who doesn't think there's much to do.
The Press
The press is quick to seek out the exciting story, the political outsider that says something that sounds radical, but almost makes sense if you haven't thought it through. These radicals are the basis for our political system as it now stands. A candidate that says, "Let's try to carefully maintain what we already have," just doesn't make for a lead story.
There are political groups that regularly get press for saying poorly thought out ideas. Green Party candidates have a long list of decent ideas ignored after being quoted as saying something similar to, "everyone should be required to ride a bicycle to work." Besides the impracticality of this on an "everyone" scale, and the implications it would carry for public transportation, and those who don't know how to ride a bicycle - or physically can't ... This is the only idea that gets press. The one that is likely to alienate most of the voting public.
What Issues
So we are left with picking politicians based on issues. In my view, most important issues, have very few points of debate. It is usually a case where the desired end-point is well agreed, but the road to get there is hotly debated. This is like the primary rifts between Liberals and Conservatives. In any case, when the desired end-point is the same, it's really hard for anybody to really care what the differences are. That's when the road becomes an attack point by the other side. Why does the road become an attack point? See "The Press" above.
The side affect of attacking the road is that the issue becomes side-lined for the debate about how one road is inherently evil, while the other is inherently good. Those that follow these debates closely, and the only ones who would bother commenting, are the same ones who believe that the issue "is" the road, and not the end-point. These people, by majority, are radicals.
What Remains
What remains are the issues that are deeply entrenched, and unlikely to be solved by any single election or candidate. Abortion, Death Penalty, and War Ending. All are good for quick headlines, but all of these types of issues are the ones that a great deal of people have strong opinions about. In most of these cases, both sides are right about all of the issues that they talk about.
So, we are left with a system where only the radicals get heard, and only the skillful candidates that can express enthusiasm and empathy about nothing in particular are the most likely to be elected. How sad is that?
Win an election based on personality alone... a pretty radical idea, if you think about it. When that sort of person gets into office, the only voices they hear are the radical think tanks.
The Majority
The majority will not be heard, because the Majority does not think things need to be radically changed, and so few think it's important to speak out in support of what they already have. The majority loses again.