I think theres a reason for small class sizes. The reason that taekwondo has become so succesfull is because of the simplicity of the art.
Kids can kick and punch with ease, looking in the mirror they look like Bruce Lee. Circular arts are difficult to say the least. Theres no foolin, with circular arts.
It works or it doesn't.
Circular arts are skill arts. Striking arts are not nearly as skill full. You can be very effective as a striker if your fast and powerful. Not neccessarly skillful. Look at Bob Sapp, mma fighter. He is a goliath, very limited skill but overpowering. Yet he is successful. Circular arts can only be learned over time, natural ability helps but is not a substitute for seasoning. The dedication that these arts deserve, is difficult to find in people these days.