My experience with buying and selling is that items that have original packaging make the market broader and in general garner a higher price and sell quicker. Many buyers won't consider buying without it. It is not because material is not available to pack items correctly. It is that you have to trust someone across the country that you don't know to properly pack an item for shipping without the original packaging. There are far too many that can't or won't properly package an item for shipment. It is not cheap to package delicate electronic equipment properly for shipment.
I am lucky in that I have a large, dry storage building and keep all packaging no matter how long I intend to keep an item. When possible, it is best to have it on hand..