That's self destructive behavior on a planetary scale. No species that has an instinct or culture to consume all available resources will survive long enough to

That's self destructive behavior on a planetary scale. No species that has an instinct or culture to consume all available resources will survive long enough to do it on a galactic scale. Also, the math doesn't work out in the sense that if a species that had this instinct reached interstellar travel a million years ago the Milky Way galaxy would already have entirely been consumed. That's the Fermi Paradox in a nutshell. If the species you are describing exists, they must have just started eating the galaxy, because the galaxy would already be eaten in an blink of an eye on the cosmic timeline. Lets suppose that it takes a ten thousand years to reach a star system and consume it, and the swarm needs the resources of an entire star system just to build 2 more probes. That means that the number of star systems consumed doubles every ten thousand years. At that rate it takes no more than 50 generations, or half a million years, to consume the entire galaxy. Note that if the number of probes the Von Neumann swarm builds is more than 2 per star system consumed, this process happens even faster.