This is exactly what I fear will happen with OP too, it will feel like all for naught then. Naruto feeling like the Zelda series with eternal destined strife or so.
A OP prequel showing Rogers rise, Yonkos rise, Admirals and Garp, Sengoku, Zephyr etc early days, Rocks pirates, Brooks full past, maybe some of Kurehas, Shanks, Rayleigh, Giants etc could be godly tbh.
I doubt we'll ever get one though.