Smart Phone Plans

Recently, I am researching the price of owning a smart phone, which is composed of the price of the phone and the monthly service charge. Regardless of which carrier you look at, the same result always occurs: Pick a voice plan that suits you, add $30 to $40 for the data plan, and extra if you want text messages. 

Although I think they are too expensive, voice and data plan are easy to understand. The thing I don't understand is text messages. Why do cell phone owners have to pay more for text messages. If the marginal cost of transmitting phone calls is low, then the marginal cost of sending a text message can only be lower. 

The cost of sending a text message is lower because it uses less resources on the network. Cell phone carriers should be encouraging users to send more text messages and make less phone calls. Charging extra for text messages is definitely not encouraging them to do so. 

Besides, there is no difference between a phone call and a text message. They are both 0s and 1s. There is no reason for carriers to distinguish between them.

In a prefect world, I would like to see just one plan: a data plan. Let the users decide how to use their plans.