interesting theory although it gives me maybe a more accurate idea as to whats happening, the game isnt saving and/or incrementing the campsite progress correctly? and if progression only happens on specific day numbers then that opportunity is just gone. maybe??
i will also note something that i didnt think was relevant but probably is, the valley picnic also had this issue. the warp arrows and warp arrow toys appeared and the empty shrimps did, but the picnic blanket, basket, and other foodstuffs didnt. neither did the event where you hear one of them running away when you approach. however, the... "occupation"? box DID still exist so you could drop food there and +-rep so...
...tldr bro idfk this game is a cardhouse with some of the cards randomly replaced with jenga blocks