Well, there's a lot of factors this.
1) Student Loans
Maybe people with degrees get them from student loans. And student loan payments are generally a large sum of money. Now correct me if I am wrong, but if someone is employed they usually can't get their loans deferred, even if the wage they are earning is too low to pay them off. So someone can get on unemployment and defer their loans until they can get a job at a salary that will help pay off those student loans.
There may be jobs in a certain area. However, not everyone who is unemployed can get to those areas. If someone is on unemployment, then they may not have the money to move. Also, there may not be adequate transportation to get the unemployed back and forth between their job and their homes. It may just be me, but public transportation is pretty piss poor in this country. Also, many streets don't have bike paths and sidewalks separated, and that's even if a road has a bike path or sidewalk for it. That makes pedestrian and bicycle traffic very dangerous.
"Unskilled labor" is really a misnomer. Pundits generally use unskilled labor to refer to employment that does not require a degree to be trained in. That does not mean, however, that the work is so simple that it does not require training. If you don't know how to check in inventory and properly place it where it belongs, then you're going to **** up the entire store and cost it money. If you don't know how to flip burgers properly, then you're going to **** up the entire diner and cost it money. If you don't know what you're doing, then you're going to cost that business, no matter what you do, money. So some training is still required for those jobs, and so previous experience still counts for some business owners who don't want to take on the costs of training a temporary employee. That can cut some people out of a job market right there.
There's a lot of bosses out there who don't treat their employees very well, and the lower they're paid the worse they're treated. That can mean a lot of physical and emotional abuse gets heaped on them. This is made even worse by the fact that employee rights aren't very strong in the U.S. Why should someone get a low wage job and get **** on when he can instead stay home and chill out for the same amount of money? There's also less of a chance he'll get hurt, so he won't need health insurance. That's even if a company provides it for them - not every business, especially small businesses, can afford to do so.