Simple. when the kung-fu movies of the early 1970's made such a big splash many people wanted to study Kung-Fu or other martial arts. The Asian countries all sent many instructors to western countries to fill that. In Korea the martial arts are controlled by the government. They saw an opportunity to make money. They sent planeloads of instructors to the U.S.A and other countries. Many of the instructors were sub-standard. A few were highly respected in Korea. Some were not even black belts before coming to the U.S.A. many of them were given promotions for coming to the U.S.A. They were the first schools to require contracts and have high prices for training. They were the first schools to sell black belt contracts.
In the late 12060's or early 1970's Blackbelt Magazine published the findings of a large study ot teh martial arts in the U.S.A. (All styles).
* Less than 3% of all martial arts students EVER reach black belt.
* Of those that became black belts less than 50% of them ever reached 2nd dan black belt.
Children were basically non-existent in martial arts schools. It was to rough for them. I saw many adults quit after one or two classes. Training was long, and tough. Sparring was a major part of most classes. Fighting at many schools was hard contact. We had no hand and foot pads. Injuries were normal.
So why did Taekwondo become so popular...? It is due to the hard nosed business and sales practices they used and still do. It attracts many students because people like the flashy kicks.
Lowering of requirements for promotion, automatic promotion of students at regular intervals, and the lowering of ages requirements all contributed to the mess we have today.
In fairness I will say this.... I have met many Taekwondo stylists. The ones I met in the late 60's and early 70's were deadly. A few today are also deadly. Unfortunately, much is no longer taught and what is is watered down for mom, pop, and the kiddies. It has become a look good feel good activity. In many schools it is nothing more than a high priced baby sitting service that hands out belts. In the 60's there were o children in the martial arts, so there were o children wearing black belts. Now children are more than 85% of all martial arts students in the U.S.A. Trying to compare the average martial arts class of today to those of the 60's and 70's, is like comparing a bicycle to a Lamborghini.
Martial arts training and research over 46 years, since 1967
Teaching martial arts over 39 years