A lot of turkeys were overcooked before the days of probe thermometers. I think that is why turkeys took longer to cook
Also, the turkey company will try to cover their butts by giving you the longest possible cooking time so you don't end up with salmonella. Of course, these are just my crazy theories and have not been scientifically tested.
Understand, when you eat meat, that something did die. You have an obligation to value it - not just the sirloin but also all those wonderful tough little bits.
Anthony Bourdain