You're making a huge leap there based on zero scientific evidence. No one has ever demonstrated maximum lifespan extension for mammals living in the wild. Experiments have been limited to animals living in nice safe, sterile cages. There's no free lunch in genetics and modifications that increase maximum lifespan are likely to result in other undesirable changes. Like suppression of immune response can be helpful but that comes with a huge obvious downside if you're ever exposed to random pathogens. Outside of some very limited genetic defects it's usually impossible to alter a single trait in isolation.