> The sun! That? Nuclear fusion. That? Gravitational potential! That? Etc... Minor pedantry on top of pedantry. The gravitational potential energy of a collap

> The sun! That? Nuclear fusion. That? Gravitational potential! That? Etc... Minor pedantry on top of pedantry. The gravitational potential energy of a collapsing protostar gets you past the activation barrier for nuclear fusion, but isn't itself the source of energy beyond that. Think of it like lighting campfire using friction. The friction heats up the kindling, but that investment allows you to access the potential chemical energy of the wood. The gravitational potential energy is converted into heat, and that investment allows you to access the potential nuclear energy of the unfused hydrogen.