Ah... the good old fruit that was the backbone of Doflamingo's rule in Dressrosa.
We all know that the Hobby Hobby fruit is EXTREMLEY POWERFUL. It turns a person into a slave toy and removes said person out of everyones memories.
Now this power is somewhat..... fishy.
What if, and this is a very questionable if, the 20 Kingdoms 800 years ago, used this same fruits power to erase all knowledge of the Great Kingdom and events of the Void Century. Its perfectly plausible. The people of Wano, seeing this coming, then recorded history on the Poneglyphs. The user of the fruit was then kept protected in secrecy until the first generation of people who knew what happened died, then the knowledge couldnt have been passed on.
Its really possible but at the same time, not possible. We know that the fruit user doesnt age so them dying and the spell breaking isnt an issue. They can be kept alive until a few hundred years, after which the common folk wouldnt also know what.
Lemme know what yall think.