you do not have to pay. you can do it for free by yourself. there is just a lot of papers, and the language used is confusing to people and they choose to get assistance.
Any person who do not is just valuing their time more than the cost of tax preparation services. FWIW, I only spend about four hours every year doing my taxes myself. Which is less than the time needed to research a tax preparation service, communicate with them, and then check the results.
The docs are pretty well written...