The liberal myth about the Republican party is that it is a party of secure privilege. But, no political party can manage on privilege alone. There simply aren't enough people who identify themselves as privileged. No, the Republican party is, perhaps more than anything, a party unified by the fear of people with something to lose.
Liberals are uncomfortable with even acknowledging the kinds of fears that drive the Republican party. Republicans are terrified of crime. They are afraid of central cities. They are afraid of blacks, Hispanics and immigrants of all stripes. They are afraid of Muslims and atheists. They are afraid of bad schools, bad influences and questionable boyfriends. They are afraid of bad discipline and loose morals. They are afraid of government. They are afraid of the rest of the world. They are religious because so much of their fate of beyond their own control. They value savings and investment because they fear that a downturn could hurt them. They fear universal health care because they fear it could compromise the plans they have for themselves or bankrupt them with high taxes. They fear having their jobs or livelihoods offshored or otherwise endangered. They are not confident that it is possible to take care of everyone and want to put their own families first. Republican men are afraid of loosing their manhood -- no Republican would even joke, as Howard Dean did, about being a metrosexual. Republican women are afraid of the social fabric coming apart at their expense.
I've always lived in cities or small towns, so it has taken me a long time to understand, to believe in the existence of, the fears that drives suburban geography.
Republicans want cars rather than buses or rail, because they fear crime (or at least discomforting breaches of etiquette) from their fellow passengers. Republicans want cars and offices to be accessable only by car so that people too poor to own cars can't bother them their. If you are surrounded by people who have, you restrict your worries to outsiders and want to make it hard for them to reach you.
This isn't the only reason that Republicans want to live in the suburbs, of course. Schools in neighborhoods where no one poor can afford to live are going to have higher test scores and the belief that schools with higher test scores are better is widely held, although not necessarily accurate. The high cost of urban real estate is also a major factor. Urban neighborhoods that most suburbanites would consider living in (with race, schools and crime all factoring in as major concerns in how those decisions are actually amde) are very expensive compared to suburban neighborhoods that they would be willing to live in. A 1/15th of an acre city lot in Washington Park is worth about $150,000. A much larger lot in the suburbs can cost as little as $20,000.
This post isn't devoted to finding solutions to all of those fears, but until one comes to terms with the insecurity of those voters, one can't even begin to win them over.