Yes some people do. I wear a cowboy hat. The stereotype is not true that you may have heard or seen on TV. They are not very common. I would say about 5-10% of people wear them. You will see more of them in Fort worth, which is about 30 miles west of Dallas. Even in Fort Worth there is not many more people wearing them. Hope this was helpful.
There are people in Dallas, Texas who wear cowboy hats. People everywhere wear cowboy hats. I live in Arizona and people here wear cowboy hats. When I lived in the state of Washington, I had friends who wore cowboy hats.