It was part of the 4th dimension/time theory advanced in the movie.

With each reset, more and more things slipped through the loop and aged or disappeared(fruit and flowers for starters, then the fish, mirror, people, and almost everything else). I believe had the resets continued without the character resolutions, reality would has popped out of existence for the main two characters.

It was part of the 4th dimension/time theory advanced during the series.

With each reset, more and more things slipped through the loop and aged or disappeared  (fruit and flowers for starters, then the fish, mirror, people, and almost everything else). I believe had the resets continued without the character resolutions, reality would has popped out of existence for the main two characters.