The answer is very simple: “because then it wouldn’t work”.
If it were possible to teach this technique through books or through the Internet, the technique would never have been lost, because the books that TM derives from have existed for thousands of years.
But exactly because it’s a natural technique, the correct practice requires personal guidance from a certified teacher of TM. “Natural” means something different to each individual. Everyone is different and requires personalized, adaptable guidance by a trained TM teacher. However, once the correct guidance is given, anyone can transcend, within the first few days. After this, the experience will be ingrained in one’s memory and the mind will almost automatically go back to that experience. Later, further guidance by a TM teacher will, on occasion, still be required to assure the student of this natural process in the first few months of practice, and to answer questions that usually come up during the practice.
If you practise TM correctly, this one simple technique can offer results that can’t be bought (being yourself, happiness, good health, intelligence, etc.). But in order to assure the correct practice, sufficient personal guidance is essential. Even though the TM organization is a non-profit organization, this requires considerable time on the part of the teacher and they require an income for their time. The reality is that most TM teachers currently earn less per hour than a physiotherapist or hairdresser.
To learn TM and enjoy the benefits for a lifetime is less expensive than the cost of one day in the hospital. But that day in the hospital is usually paid by our health insurance.
So the question shouldn’t be why there is a cost to TM. The question should be why a technique that is backed by scientific research, that has been available for 40 years and works to solve the real cause of many health 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 to the extent of billions of dollars, given the population.