Stacked cages aren't necessarily bad, but they are much harder to make a comfortable, happy environment for any living creature. Happy quail will have a dirt or sand bath. They need a place to rest their feet from the wire or they are likely to develop foot issues.
Commercial breeders usually keep males for six months, females for about a year. A coturnix quail has a natural lifespan of 2.5 to 4 years. I can't say that the commercial way is wrong, but it's not right for me. I raise my birds in pens on the ground. They get plants, hiding places, and as much as I can give them for a happy life.
If you are raising quail for maximum production of meat and eggs, then raise them like a commercial breeder. If you want them for meat and eggs, but are more concerned about their quality of life, then you want to give them a more natural environment.
There are a lot of right ways to raise quail. There are a lot of wrong ways too, but my way isn't the only way.