With that kind of prolonged behavior pattern, it looks like a lifestyle choice to me. There are people like that all over the rural areas, not just transplants from the city but native country people as well.
We have had 'tent cities' here in western WA for many years now, and they are similarly filled with people who choose that lifestyle. Often times these tent cities are set up on Church property or in various parks or other open public land. It's always the same M/O, the tent city moves into an area and the media coverage sends all the good hearted people to bring truck loads of supplies and food for the unfortunate tent city residents.
Initial media coverage indicates these folks have fallen on hard times and are just there temporarily until they get back on their feet. After about 3-4 weeks go by there are reports of increased crime in the area. Several local radio shows have done some investigative reporting by embedding a reporter for awhile. It has always been the same report, 80% of the residents of tent city are the same people that were there the year before, and the year before that...
Having said that, with this economy there has been an increase in people who do not choose that lifestyle but have been dealt those cards recently. I do quite a bit of camping and have noticed more families "camping"/living in tents or RV's in the campgrounds. In many cases these folks are 'working', but at a fraction of their former income. They have to move every 14 days so as to remain under the stay limit for most campgrounds around here.
There has also been a noticeable increase in 'urban' campers who live in their RV and park in vacant commercial building parking lots, store parking lots, park and ride lots etc. They too must move frequently to try and stay under the radar and not wear out their welcome in these parking lots around the community. I know of one such older couple who now live in their older motorhome while one of them works part-time at home-depot. They said it is less expensive for them to try and stay in the urban parking areas vs staying in an outling campground and have to communte to work and for services. Their situation is somewhat similar to the people in the OP's picture in that for the most part they have no electricity, running water, or septic (they dump the septic once per week at the local RV park).
Hopefully things will improve for those folks who did not choose this type of lifestyle and they can get back on their feet in time. There are a number of websites now that provide tips and techniques for temporarily living out of your car, RV, tent etc.
After losing homes, families move into tents | tennessean.com | The Tennessean