Shawn Johnson - who trains about 25 hours a week, attends public school, has a great and nurturing relationship with her coach, and has trained at the same gym in her hometown since she began gymnastics without ever leaving home, and outside of the gym lives a regular teenage life - has certainly shown that not only can gymnasts be trained without the overwork, injuries and psychological abuse, but that these smarter training methods are far more effective at producing prepared, consistent, and competitive talent.
The use them until they break philosophy worked in the 70s when difficulty was much lower. With today's gymnastics, sports science, nutrition, psychology and modern effective training methods are crucial if gymnastics are to make it to the competition floor without major, hampering injury or mental breakdown. In this respect, the Chinese have been smarter about their training system - they have an off-season of winter training where they stay away from hard landings, working on developing skills rather than staying in competitive shape (when athletes stay in competitive shape too long they are more prone to injuries due to lower weights and more stress on their bodies,) have hired sports psychologists to deal with the pressure of competing, focus on specific events rather than forcing all gymnasts to train events they will never be competing on, thus increasing the strain on their bodies with the workload of extra apparatus (the USA still can't grasp the concept of 3up 3count team finals which favour the development of specialists who can score highly on one or two events) are properly stretched and conditioned and undergo dance training and development of properly technique on basic skills which helps with preventing injury, and generally train and compete smarter than the American girls. This is not to deny that their system, like any elite gymanstics training system, is brutal, but they are right now doing a more intelligent job of making sure their athletes are developed and competing at their full capabilities than the US system.