The only problem I can see with Larger than necessary enclosures is the larger it is the more of a pain it'll for the snake to get its food. There is no comparison between a tank and the wild. And why would a snake probably die if its natural environment is simulated? I doubt predators or uncontrollable weather conditions are gonna be placed in with snake lol... If the snake is eating and drinking regularly, has a secure hide in a warm and cooler end, and the owner doesn't mind the upkeep,cost, and staring at bunch of decor then I think thats all the justification he or she needs!