Iron sharpens iron. Having the players working together helps push each other to outdo and outwork each other...at least for the competitive ones. I don't think you need to be watched on every single swing during a lesson. Group lessons for the instructor allows for more kids to hear the same thing at the same time. However, there is value in some one on one time to help tweak some things that need work.Well, you've got the number wrong, it's $40!
Doesn't matter what the poll results are, demand far outstrips the supply of classes as they are all sold out across all age groups and types of hitters.
The group format give tons of reps, two machines, couple tee stations, and a live station.
Regarding the head of the org, there's more than a couple reasons why you'd want to be in those lessons, you put 2 + 2 together. The whole place is a one stop shop which IMO is very good for the game of softball, at any one time there 100+ players improving their craft at the same place.
Most of your improvements will be done when doing reps on your own. I think of golfers. Go to a lesson, bring what you learned to the range. Work on it. Take it to the course. Back to range, range again, range again. Play a round. Go back to the lesson for feedback on what you worked on. Rinse and repeat. At the younger ages in golf, most lessons are done in groups.