Why don’t homeless people from states with freezing winters move south?

Not to sound insensitive but I live in a city that gets really cold in the winters and I can’t help but imagine how miserable the homeless people I see must be. It was always of my belief that if I were homeless it would not be too hard to catch a bus to somewhere like Florida where I don’t have to worry about freezing to death, and yet these people choose to stay put.