Yeah, I think people freaking out about polls are making a very very naive assumption about the country. Hillary is doing great for a modern election, even in the tightest polls, but people actually think this country isn't super racist and will reject Trump if given a better candidate.
I really hate to be the bearer of bad news on this one, but Obama himself would only be running like a point or so higher than Hillary (she does hold the 2nd and 3rd place for most primary votes ever, right behind Bams). Half of this country doesn't really care about policy as long as the culture war is fought for them. They don't care about child care, or health care, or tax code, or foreign policy. The only thing that matters is having a strongman stand up and say "You know what, you pussy liberals. Shut up, sit down, and mind your manners. If things aren't like Leave It To Beaver, then we'll make them be that way. And if they are, then you'll damn well like it."
The GOP base (and indeed half of the country) is just that racist. Donald Trump is running on a platform entirely built with culture war as the planks, and he'd be doing just this well against Barack Obama right now. It is what it is.