Random thoughts: Why are the traditional martial arts practiced by many people difficult to be used in actual combat?

Took over the backward actual combat technology. There are so many masters in so many schools in China that professional boxing can earn hundreds of millions, but it is impossible to jump out of the circle of succession. Taking over or hand-to-hand combat is one of the technical cores of all kinds of kung fu from south to north. Of course, China Kung Fu also has many unique advantages, but taking over is obviously not.