That guy specifically was transfered and had plans to stay. He actually brought his wife and newborn daughter some time later but was still living in a shared home (not the same with 8 other people, but still).
Well in some cases its because some people initially like to live in a shared home with someone who speaks their language, get more comfortable in the new land and then move out or it could be just be that guy was being paid less and wanted to save money.