He got as far as the general because he was the better candidate.
What made him the better candidate? It was the historicity of his run, which was comparable to the historicity of Hillary's, and didn't carry the baggage of being a third Clinton term.
If Obama had not been black, then the historical element would have been gone. Nothing about him other than his color qualified him to go up against Hillary's and Edward's network of donors. He simply wasn't ready as measured in terms of political experience.
I don't know where you are on 3rd parties but lets look at in the context of the 3rd party question:
You vote for one or the other because you vote for the lesser of two evils right? Well, most people do anyway....
Put a 3rd choice into the mix and they get attention. The reason 3rd parties don't get anywhere in the US is because people don't want to waste their votes on illegitimate candidates .
Obama was basically the 3rd party
After Iowa was won by Senator Obama the question of legitimacy was answered. Again, Senator Clinton didn't help herself any by running the "inevitability" offense after losing the first caucus. Read
Game Change you'll see firsthand how dysfunctional her campaign was.
I agree that Obama got a lot of help from his race and the White Guilt that many Americans had. But that wasn't the only thing he had going for him; not by a long shot.