Inept handlers: weak, unstable, inconsistent, will create insecure dogs, dogs who do not trust the owner to protect them. The dogs are on a tolerance spectrum of sorts. A soft dog might tuck tail and try to hide behind the owner she has no faith in, but will not be aggressive. A stronger dog might bark and lunch, snap and even bite a perceived threat. This is not dominance. It is protecting oneself, when the owner has given no indication that they have things covered.
Some dogs with inept handlers will learn that certain behaviors get them what they want. grumbling near the food dish gets people to back off and let him eat in peace. Grumping or snarling when being groomed might stop the behavior. The initial fearful behavior worked and now they have learned to grump, snarl, or snap when their feet or ears are being touched.
This is not a comfortable place for dogs. They have no trust in and no communications with the people that own them. They are basically in a constant survival mode. I don't see this as dominance. I see it more as a dog whose response to instability and inconsistency is a failure to trust.
Owners who fail to recognize a shut down in training and call it stubbornness are going to punish unfairly. Owners who have unrealistic expectations for puppies will create problems like this, and those who press the pups into situations lacking confidence, the pups will eventually protect itself and learn that the behaviors for protecting itself, gets him what he wants. He learns to be a bully.
As for packs. I believe they begin for the most part as a breeding pair, and the first litter, in wolves one litter per year, then the second litter. Certain pups, because of their natural pack order will run with the sire and dam longer and others will break away from the pack and start their own packs. I guess I see less harm in seeing it as a family structure, than the alpha-dominance shtuff that people try to use to relate to their dogs.
There are pack behaviors and pack orders. But in domestic dogs, I think it (pack order) really doesn't relate at all to the human. Dogs are smart. They know we are the human and they are the dogs.