[colechristensen]

Very large stars live very short lives.

Our star will live 10 billion years, the smallest stars will last trillions of years, the largest stars live less than 10 million years and some very early stars broke the models for how big they were and maybe lived much less long.

What happens is their cores go through stages of fusing an element until they run out, gravity takes over and shrinks the core until the next element ignites, fuses, and runs out, down to iron. At one of those stages the collapse triggers a supernova (or one of the class of ways a star can die) instead.