How I think Otzi died.
I believe Otzi died due to being attacked by someone else. I think this is the case as this seems the most logical to me. I say this because the evidence really pushes this theory through. Here are the facts:
Otzi had stab wounds on one of his wrists, proving he was fighting or resisting someone else with some sort of weapon. Plus, he was living in the Copper Age, proven by his copper axe. This means someone went ham on him, successfully killing him too. Possible flint spear or arrow stuck in his thumb shows he was recently hurt as it had no scar on it. Archaeologists also have knowledge on warriors around that age fighting on mountain peaks, so if that doesn't persuade you, I can almost guarantee definitely none of the others will as they are far less believable.