Artificial entities can reproduce through mass-production. This means rates of population growth radically above what's possible for biological organisms. In any given area of the universe, we may see the habitable areas being saturated with such entities, so that even while the civilization expands in all directions into space to become enormously powerful, each individual lives a squalid existence competing with millions of other digital people in every cubic kilometer.

This is a worst-case scenario that deserves serious research to ensure that it would not transpire before we even entertain the possibility of allowing IDL to emerge and gain a foothold.