A lack of funds.
That's an all too common barrier to escape these days, but a person's motivation level has a lot to do with it too. If you perceive the threat is great enough, you'll find a way to move to safety.
As an example; during the Great Depression, both of my grandfathers loaded their wives and kids into their jalopies and headed to California to find work. They were men of almost no means at the time, but conditions were so dire in the Deep South, that they were motivated to overcome barriers you and I would consider insurmountable, to get their families out of there.
When my wife and I decided to uproot ourselves from California, we were sufficiently motivated to figure out a way to do it on just the money that was coming in from paychecks. I look back and still can't believe we pulled it off, but we wanted out that badly.