It is easy to speculate the FDA may at some point ban melatonin as a food additive .
Except that's not what I'm saying and neither is anyone else because it's already illegal to use it as a food additive. It's not illegal as a dietary supplement and I'm not suggesting it ever will be.
The discussion, one more time, is about the size and shape of the package the product comes in. If it is packaged as "a conventional food item", then simply slapping the words "dietary supplement" on the package doesn't change what it essentially is. Right now, there's a loophole where applying label makes it all OK, but things can change. An action aimed at closing the loophole is already underway.