The legal profession goes back thousands of years. Early civilizations began to codify laws and thus created the need for individuals who specialized in understanding and interpreting those laws. The more laws on the books, the more time lawyers had to spend studying to understand and master them. Eventually the practice of law evolved into a complex legal system that includes lawyers, judges, and many supporting staff.
Everyone recognizes that there is a difference between a country lawyer and one who practices in the city. Popular culture tends to depict the former as good ole boys who have law offices in their homes and are friends with everyone while the latter are shown as heartless shysters who only care about making a reputation for themselves and making money — even at the expense of their clients.
Neither of those portraits is accurate.
The major difference between rural and urban law practices is complexity. Larger populations require more laws and the relationships between people are more fraught with breakdowns in communication and outright disputes. The lawyers in a Salt Lake law office will probably be specialists in a specific area of law, like criminal law, family law, or contract law while someone practicing in a small town will handle cases in all of those areas as well as many others.