We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
State of Rhode Island enacted licensing for Telephone and Communications work about fifteen years ago. Anyone that could prove prior job experience (pay stub from a company they recognized as in the industry) could get a license immediately, "grandfathered in".
Once the licensing was in place the new state inspectors started coming by. All with their hand out. License or not, if you weren't a union job they could and would harass you. On any large size job at least one person could be counted on to forget his RI license, and for a out of state, non union company that was enough to get shut down. For the first few years, RI didn't have any printed regulations or codes for our low-voltage wiring, so the standards were whatever the State Inspector said they were. The local union guys that we worked with, confirmed that the local union shops only saw the Inspector when he stopped by for coffee and his skim.
The whole scam was clearly designed to keep out non-union, out of state workers. That worked for me, I hated to work in RI.
Trade unions (associations) are exist to protect their own interests and that includes restricting the number of people who can participate.
River/harbor pilots have been doing this for years. On the Mississippi there is one family who has been doing the piloting from Pilottown to Baton Rouge and has since the mid 19th century. Another family from Red Stick to St. Louis. Boston Harbor, New York Harbor - all have their "groups" of individuals who only once in a blue moon allow somebody to enter their closed society.
As stated, it can be about profit and money, but mostly it is about "control" - control of an industry that becomes dependent on your expertise.
Licensing is an excellent example of a power whose genuine need is limited to a few matters directly impacting public safety (driving, operating nuclear reactors, etc.), but which is expanded to apply to areas where simple caveat emptor is sufficient.
Getting a good fix will require a constitutional amendment, mainly at the state level (where the majority of abuses occur).
A shirttail relative became a well-known doctor without going beyond sixth grade, if that. In the late 1890's/early 1900's, he simply "worked" his profession under the guidance of other physicians and surgeons. My father-in-law never went to law school, just "read" the law with a gentleman who had passed the bar. My grandfather taught in a one-room schoolhouse for three years while putting himself through the U. of Nebraska. He had no teaching certificate, but was a master communicator and became head geologist for a major gas and oil company.
Now these jobs require much more education, but in many cases licensing is merely a power play to keep the profit pool small and self-serving. Any "American (fill in the blank) Association is suspect. Research the American Medical Association if you want your toes to curl.