Eiichiro Oda is the George R.R. Martin of Japan they're on 90+ volumes now just end it at a 100 and call it a day. Let some other writer & artist do a spin off set x years later ala Boruto (but with One Piece I'd rather it be hundreds of years later)
I doubt that will happen. Given that there have been manga totalling 200 volumes in Shonen Jump, I doubt the workaholic Oda will ever stop.