A need for personal service is not a sign of elitist character, but a natural phenomenon in a service society. Personal trainers have already proved their worth for people adopting a healthier lifestyle, but their popularity also demonstrates people's willingness to pass on responsibility to others. Changing your lifestyle is a major task that requires you to leave your comfort zone. This requires a personal coach to provide motivation through encouragement, coercion and rewards to achieve the set goals.
A personal trainer will not sweat, run out of breath or refuse unhealthy food for you, but they do promise success. The medium of exchange is money and reputation. It is not worthwhile for a personal trainer to promise permanence, since then they would run out of work. On the other hand, maintenance and updating are necessary to make change permanent and make it worthwhile to purchase the services to the grave.