After reading the latest chapter of Aot (99), I am wondering if Karl Fritz, AKA the 145th king was responsible for why the Founding Titan can only be properly used by members of the royal family. It essentially states that his vow of pacifism with the Founding Titan hindered on the fact that his successors must be of royal blood and that if it was inherited by a non royal blooded Eldian then this vow of pacifism would be broken. So is the 145th king responsible for why Eren can't use the coordinate or has it always been this way?