The problem is it doesnt teach the basics. It's too sterile environment for that stage of development and they should be out in the field around noises etc. We had puppies almost sitting on top of a running lawnmower in class today, I'm cheaper then most puppy schools. Would you rather your puppy do that or sit in a sterile vet office. Dogs should go to dog school if you have not owned or trained a dog before. Ongoing help while the dog is developing. If people want to charge you hundreds of dollars to just sign up for group classes, well unless the dogs spin plates on their paws find somewhere realistic.Puppy preschool isnt there to replace proper training .... its more about training the humans how to deal with their new pup food wise and very basic training, toilet training, seperation anxiety, basic socializing etc etc. Its better than nothing at all like most people choose to do.
Look at it as exactly the same as childrens preschool .... it's a great way to teach the kids the very basics before primary school starts.
Nothing wrong with it all and "throwing it out the window" would achieve sweet F all except maybe make more money for those that run their own training schools.