That we aren't even close to the end lol. Like at all.
I actually consider Wano to be possibly the end of only 2/3rds of One Piece. There's just way to much shit to do and Oda, not once, as has ever really tried to rush the ongoings of his story (save for combining certain arcs, etc. which just made those arcs even longer than needed tbh). I'm honestly expecting the series to hit 1400-1500 chapters by the end. This will be a shock to people, but once we finish Wano and we inch closer to Chapter 1100, people will realize how much this story actually needs to address and how little Wano actually achieves (defeating a Yonko or not)
So yes, I see another 10 years of OP easily, especially as we get closer to the end and Oda to quite literally combine all facets of his story together for one final, massive arc (which may even be 150-200 chapters in on itself). Imagine that this "final arc" doesn't even begin within the next 100-200 chapters if there are more arcs before it lol.
To compare: Naruto's "final arc" was nearly 30% of its whole story, trying to tie together ALL of its lose ends and characters before it ended. Now imagine One Piece trying to do the same, with a world that is much bigger than Naruto's and an overwhelming wealth of characters that have been setup for this final conflict. Now realize that we aren't even on this final arc or the fact that there will likely be other arcs before it and after Wano. Then realize that we aren't even close to finishing Wano to even get to that point.