Did everyone forget that if there was no Wall there wouldn't be any foundries.There wouldn't be a traveler. There wouldn't be anything. We were not so dum that we died and they used are armor for Gjallerhorn. The Titan was the reason we won the Twilight Gap. We were the only ones strong enough to fend off the waves of fallen. And thus many titans died in that battle but thus the Gjallerhorn was made as well. We are the ones who preserved the Human race from extinction. Hunters if there was no wall there wouldn't be a need for a scout. Warlocks if there was no wall or tower your findings wouldn't be of any use. Everything began with the titan first. The wall is not for a titans protection. It holds inside the VERY last city on earth with a LIVING population of people that are not all Guardians.