Oda even though is the author but he isn't credible when it comes to what he says
Op will end in 5 years - we got 4 years of wano alone lol
Oda sets zoro and ryuma parallel - ends up calling Luffy parallels ryuma out of blue
And, now he says one piece will end in 3 years
And, even a teenager can easily make sense that the time limit he puts is not enough to wrap all the plots.
For Luffy to fight shanks, oda has to pull shanks is evil but how is up in the air