A few things: three weeks wasn’t meant to be full training. It was meant to teach him the most important commands - heel, come, go to bed, leave it, down + stay. And then we get additional training sessions with the trainer (i.e., after he came home) so that we learn to continue the training.
As to the e-collar, he is not going to wear it all the time (or anywhere close). He wears it only during training sessions and the idea is to have him fully off it once trained. I’m sure different trainers have different philosophies but this trainer is very much of the belief that it should be used as a supplement to positive reinforcement training.
To be honest, we had a fantastic trainer with my last dog but he never got all that well trained (no e collar). He got out when a contractor left the door open. I found him but he wouldn’t come, and when he stopped, I couldn’t get him to stay and he ran right in front of a car right in front of me. It was heartbreaking (I’m very much a “dog is part of the family” type of guy).
So with this dog I was insistent that he get trained for that reason. And we have two kids, including an infant. So my wife needed a very well behaved dog for her sanity. We spent probably a thousand bucks on training and he was still just destroying everything in house and he was an absolute nightmare on a leash (other than walks on one specific root when I was walking him). We couldn’t take him anywhere like the beach or the mall (which is dog friendly here) because it was just a disaster every time.
It’s been night and day. I don’t think an e collar is for some dogs, but it’s been very successful for him. And it has been to supplement positive reinforcement training. The system is not at all “dominance based.”