Are there independant milongas in town or is the teacher also organizing them? That is, is there any tango at all besides this guy? If he is the Godfather of tango in this "one-horse town" then yes, it's better to put your money and free time into another hobby. I've been a student in classes where the teacher used to put together people from various levels, ranging from absolute beginner to seasoned intermediate, spliiting all the people into three or four little groups and going from one group to the other during the whole class/workshop, showing different things to different groups. And from what I saw, it does not work.