Eh. Pretty much every time we've got a "the next arc is definitely this place" Oda throws in a curveball.
We have to save Alabasta- but first, adventures with dinosaurs and in Cool Cool Mountain.
Next up, Fishman Island. Took 6 arcs, a timeskip and like five years to get there.
Gonna fight Big Mom first. But wait, interlude with Doflamingo. But wait, he's Kaido's lackey, so off to Wano. But wait, Sanji's been kidnapped, WCI is first after all.
There's not much time left in the series, and Elbaf is obviously coming up sooner than later, but there's still room for a curveball. For one thing, how would the Strawhats actually get there? Eternal Pose? Vivre Card to a giant? Neither of those things are likely to be on Wano, not unless Big Mom randomly keeps them in her back pocket and the Strawhats somehow steal them.