And as to the OP, it really depends what you mean by metaphysics... devas and brahmas are just as much a part of the causal universe as are we, they are just less physical.
It is important to distinguish between Abrahamic conceptions of God and creation and their corresponding Indic conceptions. The former are outside of the laws of nature, the latter are within them. This story is not discussing the creation of the universe, just the recent past. Nor is it discussing eternal supernatural beings, it is pointing out that no such beings exist.
Really, I think the point of the story is to show that we are on a downward slope based on our ever increasing attachment and clinging to the physical. This is very much in line with the Buddha's teaching that craving is the cause of suffering. If it is not true, how could it work as evidence to support the teaching?
Upasampadā: 4 December, 2001