It's a very broad question, are you asking about some actual reasons that could lead to bitcoin's death in a normal world or in any possible scenario, even those that are quite unlikely to happen? Because let's say that there is a nuclear war or an asteroide hits earth and all the human race gets wiped out, well, in that case bitcoin would become extinct, just like us. Otherwise I'm not sure, I remember reading somewhere that bitcoin could keep going even without internet, I should look it up again because I don't recall the details but I had no idea it was even possible.