Occupational licensing is largely a crony tool that keeps poor people poor, shields incumbent players in the marketplace, and generally warps the free market/price system. This is true even in large swathes of health care.
(From Real Clear Markets)
While the existence of licensing for most health care workers (66 percent) may not be shocking given concerns about public health and safety, the nature of the rules is important to the economy. Their licenses are often costly to acquire and maintain, and health care practitioners’ activities can be legally restricted in unnecessary and detrimental ways by those same licenses.