It's not about you having to spend every waking hour entertaining her. Not the QUANTITY of the time.
It's the QUALITY of the interaction. REAL off leash tears for an hour will tire my pups out more then 4 hours of me just playing with my pup in the house/yard. Putting my dog in the car, driving somewhere new, meeting lots of NEW people is completely different from the same family friends in the house. Training in a NEW place with new distractions is also COMPLETELY different then the training we do alone at home with our dogs.
This is what I HAVE to do with my 5 month old dogs or they DRIVE ME NUTS TOO!