>>723122594
Luffy was never just some random lad or anything. People's memories are muddled by implied travel time and the anime adding in filler to space out their adventures, but the actual timeline of One Piece (as you can tell by the phases of the Moon) is fukken nuts and Luffy was always a one-in-a-million prodigy that went from being adrift in a barrel to taking down one of the great powers of the sea with one of the most powerful kinds of fruits in like, a week or two. Along the way he was constantly having shit handed to him, meeting every major player he needed to, and there was constantly talk of prophecy n' shit.
The cracks were showing as early as Drum Island and Water 7, when they were already talking about the Will of D and the way the entire crew got massive upgrades offscreen, with little basis for most of them, and almost literally overnight given the amount of time between islands. From there the foot has always been flooring the gas pedal on the chosen one shit.