Why isn't there a auto delete system for posts that has no replies for over a week?

[RedLine05]

I think there should be a auto delete system for posts that has no replies for over a week, since those posts won't be replied anyways.

 

[USAFRet]

I think there should be a auto delete system for posts that has no replies for over a week, since those posts won't be replied anyways.

There is, but it is longer than 1 week.
3-4 months, I believe.