I hope you guys don't mind a bit of a newb/outsider perspective in this discussion.
As a licensed electrician, I work in a highly regulated profession, complete with a formal apprenticeship, tests, journeyman and master licenses, and annual refresher courses required by the state licensing board. Even with all that, there are still numerous hack electrical contractors that do shoddy, substandard work in this trade.
It seems tree work is no different. I think there are hacks in every occupation, and I'm in agreement with the sentiment that the hacks outweigh the considerate professionals who truly care about their occupation and advancing it. It's frightening to see people who have 20 or 30 years experience, which means they have one year of experience they have been repeating 20 or 30 times.
As for the licensing/regulation aspect of tree work, I have the same feelings I do about my own licensing requirements. I live in a state where both trade and tree work are state licensed occupation. It's a double edged sword for me. On the one hand, I'm in agreement with the principle that a man has a right to earn a living without needless government interference. That might mean a guy with a Wild Thing saw, a 1989 dump truck and whisper chipper, or a guy with a pair of pliers, coil of wire and "Electrishun" written on the side of his car with electrical tape.
On the other hand, licensing and occupational regulation does create certain barriers to entry that tends to keep out the truly hack and dangerous practicioners. It cannot stop them completely, but it does make it harder for them. There will always be the old dump truck tree guy and trunkslamming electrician, but they are the exception and not the norm, at least in my area. In other parts of the country, it's surely different.
Bottom line for me is that I would love to work completely unhindered by the gov't and work on the principle of "Buyer Beware". But I do benefit from the protection and credentials that licensing and regulation has to offer. The problem is that gov't regulation tends to only increase and stifle business, so in the end I don't think regulation has the desired and intended affect.