> If that platform is taken away you just have some bits of data pointing to other bits of data with no meaning and no value at all..
They can still have meaning (we know what item it was); whether there are people who would value the pure notion of owning such a digital item in the absence of concrete functionality is indeed the question that NFTs explore/raise.
Yeah, someone else can create a new game and say "we accept the NFT items from Defunct Game X", you are still completely under the control of whomever is providing you the platform for these in-game items to actually exist. If that platform is taken away you just have some bits of data pointing to other bits of data with no meaning and no value at all...