Cap's shield is made out of the hardest material on earth
Plot armor is stronger.
Boba Fett was dead before he fell into the pit. And on the third decade, he rose again. As did all of the dead villains from the original trilogy. I'm still waiting for Jabba to return. And at least one from the prequel trilogy came back because, "Can you prove that an alien cut in half and dropped down a shaft is truly dead? Can you?"