I'm a bit biased as I went to a school with a great PT program, roomed with PTs, ran with many on the xc and track teams, and ended up dating and marrying a PT. A PT showed me exercises that basically cured my achilles tenditis when the athletic trainers and doctors all said I have two choices: have surgery or quit running. I have been injury free ever since he worked on me (five years ago).
In my experience with PTs, they want to fix the problem, not just treat the symptoms. They are very well-versed in anatomy and kinesiology, and their profession is backed by solid scientific research (unlike chiropracters, although the new generation seems to be a bit better than the quacks of old). Most PTs "dumb down" the exercises prescribed to patients because most people just wouldn't do the more complicated ones. I know I wouldn't.
That being said, some schools are just horrible places to learn the profession and turn out PTs that are worthless. Many are just in it for the money, like those you mentioned who cram as many patients as they can into the schedule. Some clinics are horrible too, but that happens with any profession. There always seem to be some Doctor Nicks out there.
The insurance thing is a bitch, but I can understand it because without payment from insurance companies, PTs would not get paid. And no matter how fulfilling a career is, not many people would want to work 50 hours a week for free. Also, a lot of states do not have direct access, which means all of a PT's treatment must first go through a doctor, which further complicates the issue. The billing situation varies from clinic to clinic (some are very strict about keeping track of billable hours, others are more concerned with treating the patient).
As the APTA makes more national guidelines (and as the DPT is phased in over the new decade), you will see a positive change in the PT industry. Many of the poorly run clinics will go out of business, and the quacks will have no place to practice.