Why can we still not sell items back to the shop?

The game has been out for like 8 years tomorrow (Happy Birthday) and there's still no way at all to get rid of unwanted ammo, dog biscuits, tents, bird decoys etc.

It's an incredibly basic feature that even 30 year old games had with buy/sell options in shops.

We managed to get a rename/delete option on the Dogs eventually after much less time than this so what's stopping it from happening?