Ok Wow where to begin... Lets see
Keeping the animals in a rack set up is typically for a breeder that has neither the time or money to set up and clean glass tanks for every adult - hatchling animal. Its impractical and not very cost efficient. For a keeper with only a few animals tanks are a great way to enjoy them and properly house them.

As for feeding live many laws when it comes to pets and the pet trade are "Feeling" base i.e "I feel so bad for the rat it really doesn't have a chance to escape". Bottom line the rat isn't meant to escape and keep breeding to repopulate the species as they would in the wild. Its whole reason for existing is to provide my snakes with nutation that's why it was brought into this world. Again we come to cost effectiveness if I feed F/T or P/K and the snake doesn't eat then that rat was wasted and has to be thrown out it did not serve its purpose for being bred and raise and put down. In a scene its life was wasted. Now if I feed Live and the snake doesn't eat then the rat goes back in the rack and it lives on till it serves it propose. No wasted money, no wasted life every one is happy.

What happens when you get an animal that will not eat F/T or P/K is it better to have that animal slowly starve itself to death for the sake of our "connection" with furry things. Where then is the balance of who's chance for life was cut short by our decisions.