The answer is very simple: “because then it wouldn’t work”.
If it was possible to teach this technique through books or through the internet, the technique would never have gotten lost, because the books have been there for thousands of years.
But exactly because it’s a natural technique, the correct practice requires strict personal guidance. “Natural” means something different for everybody. Everyone is different and requires a personalized adapted guidance by a trained TM teacher. However, once the correct guidance is given, anyone can transcend, from the first few days. After this, the experience will be ingrained in our memory and the mind will almost automatically go back to that experience. Later on, further guidance by a TM teacher will on occasion still be required to assure the further natural process in the first few months, and to answer the many questions that usually come up during the practice.
If you correctly practice TM then this simple technique can offer effects that can’t be bought anywhere in the world (being yourself, happiness, health, intelligence, etc.). But in order to assure the correct practice, sufficient personal guidance is essential, and this requires time and money. The reality is that a TM teacher currently earns less per hour of work than a physiotherapist or hairdresser. The TM organisation furthermore is a non-profit organisation.
To learn TM and enjoy the benefits for a lifetime, however, is not more expensive than the cost of one day in the hospital. But that day in the hospital is usually paid by our health insurance, we hardly pay anything from our own pocket.
So the question shouldn’t be why there is a cost to TM. The question should be why a method for which scientific proof has been around for 40 years that it works to solve the real cause of many problems isn’t reimbursed by health insurance, while a lot of medicines that usually only suppress the symptoms, often with damaging side effects, are reimbursed in terms of billions of dollars.
Is this the ignorance of our politicians, or the lobby of an industry that wishes to safeguard its own interest behind the scenes?