I don't understand why you think that even in a place where lots of people care about culture one can simply decide to play at a concert whenever they want, especially if they are still students. And he specifically says he's busking as an alternative to practicing at home, not as an alternative to playing at a concert.

In my limited experience, places where there is more interest in erudite music also have more people busking, not less, since there are more players overall.