According to the book, Surely You’re Joking, Mr. Feynman!, why does Feynman fix radios as a child?

While still a child, Feynman is hired to fix the radio in a hotel (which turns out to be owned and operated by his aunt). After this point, he is hired by many other people around town to fix radios. He suspects his services were in demand because of the depression (since he was a kid, he worked cheaply).