You know that small difference in the initial conditions of an entity can play a large role in the path it follows, and you further know that an entity which is spawned into a position where the light is very faint is less likely to be able to pursue it. You sometimes put new creations in which you have much confidence into initial conditions where they are very unlikely to survive, as a means of testing them (perhaps there is another "level" they are taken to to train a new feature once this stage is mastered). If they do not end up being able to pursue the light in those initial conditions, you might indeed let their information perish. But you might instead want to see if they could find the light when moved somewhat closer to it, as a way of checking if their ability is entirely busted or simply not as sensitive as you thought it might be.

> And if the goal is just to allow as many entities as possible to enjoy the light, why not relocate them all to be close to it? Why not save all of them into the next generation?

I'm not sure that is the goal, but regardless your machine only has finite resources, but is changed with presenting an infinite environment. Sacrifices must be made.