Lyle wouldn't committed suicide if someone loves him or care for him, and that's why he hasn't been identified. He must feel unloved and unwanted or being abandoned. Apart the message on his suicide note, he actually had unwritten message there as well, which was "You must remember this", that's why he took the name from that fiction and knew that once he died, the investigators would find out that his name is from that fiction. He just wanted the world to remember him, to notice him, to acknowledge his exsitance by did what he did. He grabbed attention from worldwide successfully and indeed got millions of people care for him and put lots of time and energy, trying to give him his name back.
