Most of your points are good but some of your assumptions are a little off. While I don't think any of these points undercut your bottom line, they might as well be corrected.
My understanding is that SD is almost always in the competitive range with regard to cost in the given areas where it is taught and that, often, it is on the lower end of the cost range. That is certainly true in the DC area where I train. The only martial arts schools that charge a lower tuition than the SD school here are Judo clubs, which have a history of being very reasonably prices compared to other arts.
The rest of my observations are contstrained to what's available in the DC area because I just haven't had the opportunity to observe the range of other schools in other regions.
As for efficiency of training, I have to take some issue with that too becuase I'm not sure that you're getting the AR15 with the TCMA. It really depends on the trianing goals of the individual. If fighting is the answer, I would say that the only gyms in my area that are more efficient than mine are the pure MMA gyms. I don't think any of the traditional Chinese, Korean, or Japaneses schools in my area are focused enough on high intensity training to produce effective fighters. The traditionalists in my area may have good stances and may even throw a good punch or kick but, based on the classes I've watched throughout the area, most would be so winded 1 minute into a match that they'd be done if they hadn't won by then. The grappling gyms are good but, without any stand-up training, I'd say they're more sport-centric than they are combat effective (mostly because of the whole its-bad-to-go-to-the-ground-in-a-bar thing).
If its forms and being good at forms, you've got a legitmate point. Not only are the SD forms from a suspect source but there are so many of them taught so quickly that its difficult for the average student to do any of them without looking bad and demonstrating relatively poor technique. So, if being good at forms is what you're looking for, I have to agree that SD is not the most efficient way to go about that even if you eventually can do the SD material with appropriate mechanics etc.
General fitness: the SD school in my area compares more to the MMA gyms cardio output versus the more traditional schools. Workouts in my qwoon are some of the hardest I've experienced since I wrestled in school and, frankly, are only less hard because our classes are either an hour or and hour and a half long (wrestling practice was three hours a pop, five days a week).
Anyway, as I said, none of this undercuts your bottom line.
As I type this, I do still attend an SD school. I do this becuase we are geographically isolated from most of the system (there's not another SD school within five hours of us) and, consequently, we can avoid much of the cultish stuff associated with some of the other schools (my belief is that the Soards' group has generated much of the fodder for the cult accusers). My sifu is an abo****ely solid guys and has never knowingly lied to me. He's a tremendous athlete and a tremendous martial artist. I've only met Sin The twice and have not given him any money. I've been pretty insular within the system and, consequently, am happy with the training I've received.