I have two choices for wireless in my area. AT&T and Verizon. Sprint and T-Mobile don't have any towers in my area. The nearest T-Mobile or Sprint tower is nearly 25 miles away on the other side of the county. I live in rural MD and rural folks have very few choices for services.
AT&T is in the middle of purchasing T-Mobile. If the merger is allowed to happen that only leaves three national carriers. I wish Sprint were available in my area. They have a truly unlimited data plan.