There is no update as to when the Oasis Event will end. For the Oasis Items like Seafood Cron meal and etc, you can read the Item Description, where it is mentioned that it will last till end of Oasis event. So there is no need to stock up on the items, as the Oasis item will disappear when the event ends. 

So no need to pile them up in our storage =)

When Covid Pendamic over. That where they starting to remove the Oasis.. This the assumption made by most of players.