Let's put this in perspective a bit. If it takes the average person 3 to 5 years to get to black belt, then it would take you as little as 64 to 107 days to get one with private lessons using the formula of 7-17 times faster. I think between 2 to five months is a bit quick even for the McDojos don't you?
yes, that is probably too fast, but it also assumes an inappropriate focus on RANK vs. actually learning something. I prefer to think of private lessons as a way to gain deeper and more precise understanding. This may include faster learning, but it also takes time for that learning to translate into physical skills. So while the intellectual learning could be 3 or 7 or 17 or 107 times as fast (i'm just making up numbers), it still takes time to develop the skill. I guess it's possible that rank progression could also be faster, but I think not all that much faster. As I stated, I think it's pretty difficult to attach real numbers to this. But it doesn't invalidate the value of private lessons, so long as they are done in an appropriate manner and the big picture is kept in perspective.
The USSD sells private lessons at a very high price. IMO much higher than they are worth. Any benefit that they might give you is far outweighed by that. Plus, they are as often as not taught by one of the "Red Belts" rather than one of the black belts. How much benefit is there in that?
I don't know much about the USSD, again as I stated, I don't have a dog in that race. I don't know what their business/teaching practices are, and I don't know if these practices are consistent among all of their schools. Maybe some incorporate questionable practices, maybe others don't, i dunno, don't really care.
I think the bottom line is that yes, private lessons can be beneficial and help a student learn more deeply and perhaps develop more quickly. I don't think you can attach real numbers to how fast that is. If the student perceives a value in the lessons, and is comfortable with the price, then they will do it. It's up to the individual to decide for himself. I don't see the point in going on a crusade against a specific group for what they may or may not be doing. If you don't like them, that's your choice as well, but arguing about it on the forums isn't going to change what they do.
I could go on a rampage and start dissecting all the self promotions that have happened within the greater kenpo community, and try to put every single one of the seniors under a microscope and try and hold them to task for it. How far do you think that's gonna get me? How long do you think I'm gonna remain welcome here in the forums? It doesn't matter to me, it's none of my business, and whatever I say about it will have no impact on any of them.
So choose your battles wisely and recognize when it isn't worth it and it doesn't matter.