This is how One Piece will End

No.11223392 ViewReplyOriginalReport
This is how One Piece will end.

They get to final island after all their battles against the shicibukai, marines, and government forces.

Shanks will die by government's hands somehow beforehand and Whitebeard is also killed somehow which leaves Luffy as the only surviving pirate leaders that could become the Pirate King.
Luffy kicks the corrupt part of the government's asses and brings peace between the rebel faction that his father led and the good part of the government forces before they finally create that final weapon that could destroy the world. Zoro fights Mihawk and wins while all this is going on. This peace is mediated by his old crewmate Vivi.

Marines are reformed also by his old friends (Koby and Helmeppo and Smoker) becoming the Admirals in Command of Headquarters. They come to agreement that ALL pirates need not be exterminated...only the evil ones.

So at the final island stands a single house. Luffy and gang slowly walk in with the sun on their backs. On the table stands a single coin and letter attached to it signed by Gold Roger. The greatest treasure in the world all the pirates have been striving for is actually... a single gold coin. Literally One Piece.