These box artworks are masterpieces in their own right. Simply wonderful work, worthy of being in an art gallery.
As an extra area of income, why not look into the possibility of selling these artworks as larger prints? I'm sure some people would love to have such work framed and put up on a wall.
These type of boxes help fire up the imagination just like the old Airfix box artwork used to, like the Avro Lancaster coming in to land all shot up and with an engine on fire. That box art was amazing to me as a kid.....still is!!
Much better than the photoshopped re-enactor type boxes.