Ridley made sure he made this possibility of a Creator not being immortal, evident in Prometheus. He wanted to make sure the audience grasped the idea that a Creation might outshine and outlive the Creator.
This is an interesting take on the scene.
What I interpreted from the scene was mankind's pride being cut down. The last scene in Prometheus when the awakened engineer cannot fathom why Weiland would ask such questions of origin (before killing him) underlines this.
David in the scene above essentially humiliates Weiland for believing he had achieved something special, godlike, in manufacturing him (David). So man is reminded from both sides, Creator and creation, that he is very very small and insignificant relative to what exists before and after him.