Whatever its stated purposes, in reality most professional licensing efforts are mostly aimed at using the power of government to limit new entrants, and thus new competitors, from a certain business:
In Alabama it is illegal to recommend shades of paint without a
license. In Nevada it is illegal to move any large piece of furniture
for purposes of design without a license. In fact, hundreds of people
have been prosecuted in Alabama and Nevada for practicing "interior
design" without a license. Getting a license is no easy task,
typically requiring at least 4 years of education and 2 years of
apprenticeship. Why do we need licenses laws for interior designers?
According to the American Society of Interior Designers (ASID) because,
Every decision an interior designer makes in one way or another affects the health, safety, and welfare of the public.
more than 30 years of advocating for regulation, the ASID and its ilk
have yet to identify a single documented incident resulting in harm to
anyone from the unlicensed practice of interior design...These laws
simply have nothing to do with protecting the public.
As always on this topic, I end with a quote from Milton Friedman on licensing:
The justification offered is always the same: to protect the consumer. However, the reason
is demonstrated by observing who lobbies at the state legislature for
the imposition or strengthening of licensure. The lobbyists are
invariably representatives of the occupation in question rather than of
the customers. True enough, plumbers presumably know better than anyone
else what their customers need to be protected against. However, it is
hard to regard altruistic concern for their customers as the primary
motive behind their determined efforts to get legal power to decide who
may be a plumber.
Update: This is timely, as 1-800-CONTACTS has informed me that due to various state and federal laws, they may not sell me the contact lenses any more that I have been purchasing from them for a year. I must go into an office and pay a government-licensed eye doctor to get an updated prescription. This is despite the fact that, once sized, contact lens strengths are easy to understand. Every year or so my eyes go up by about 0.5. I could easily get by still with my old contacts, or I could, if I wanted, self-medicate by adding 0.5 (the minimum step at my level of vision) to each eye and testing to see if this new setting was any better. This is exactly how people buy reading glasses (or pants, or shoes), by simple trial and error in the store. But I can't do this with my contact lenses -- or actually I do exactly this, but can only do it in a doctor's office, paying the government mandated annual toll to get my prescription updated.
Yes, I know, there are all kinds of fabulous reasons to go to the eye doctor each year, to test for glaucoma and other stuff. But why shouldn't that be my choice? The government doesn't force people with good vision to go to the eye doctor for such tests each year, only those of us with bad vision. The only analogy I can come up with would be having to go to your physician each year to get your shoe size validated before you could buy shoes for the coming year. After all, I am sure there are substantial health and safety issues with wearing poorly-fitted shoes.