I think it will be a little to extreme for a shounen to let the MC die, for a shounen that goes for more of 20 years where people all over the world love Luffy even more so, let alone the fact that after he topple the WG there is literally nothing to stop him, the only way it's a draw VS Imu (if he is the final boss). The thing on the lifespan it's clearly ridiculous, he only lost 10 years, the rest are all headcanon of paranoid fans