Ideas Portal
It would be nice if you could delete an Inventory item but still have the ability to filter it after the fact if you need to like you can with deleted products. We are hesitant to delete an inventory product because we do not want to lose the history.
I know this isn't exactly what you're asking for, but you can do something similar. Simply add "Inactive" to the front of the inventory name, and use the existing filters to find all items that do NOT contain "Inactive" when you only want to see active inventory items, and set it to find all items that DO contain "Inactive" when you only want to see the "deleted" inventory items.
This will allow you to keep your inventory history while still being able to filter seeing them in your inventory list. It is only a minor inconvenience to remember to rename the inventory item to either remove or add that phrase when setting it as active or inactive.