I think there could be many definitions of a good home. I also don't agree that puppy mill and BYB dogs often go to bad homes. Below I will list some qualities a good home will possess.
- Loving environment
- Appropriate vet care
- Reasonable exercise
- Safe environment (fenced in yard if necessary, no toxic materials left within reach..)
- Boundaries set
The things listed above would make for a good home. I provide all of these things for my dogs. I got Dakota from a garage sale, Ditto from a hobby breeder, Daisy from a neighbor who had an "accidental" litter, and Weegee came from a lesser quality hobby breeder. Of course there are many other things that create a good home, but these are the things that jump out at me initially.