Why can you auto-delete messages by age but not attachments?

Okay, so Messages has a feature where it will auto-delete everything by age (30 days or 1 year).

Great.

And there's a feature (Settings -> Storage) where you can review message attachments by size and delete them one-by-one.

I find this feature to be clumsy, but, okay.

So why isn't there a feature that will automatically delete older attachments?

The thing is, I do want to save messages from people I only talk with once every 2-3 years, because, why not. Text messages only take up a tiny amount of storage on my phone. But I don't want to save old attachments from anybody because they take up a huge amount of storage.

There should be a button somewhere to delete all attachments that are older than 1 year.

The fact that there isn't is kind of inconsistent on Apple's part.