As a part timer who thankfully does not have to rely upon the income and instructs for fun, I have to agree that the instructing industry is responsible for under-valuing itself. The stiff upper lip approach is not conducive to producing the best quality of instruction in my opinion.
Some individuals are natural instructors who would prefer to stay on in instructing and make a career out of it, but find it impossible to maintain a reasonable standard of living by doing so.
What is needed is a proper career structure with suitable rewards based upon assessment and career progression, so that the talented instructors are retained and valued.