Oda had no issue making him jump from barely YC1 to solidified top tier in 1 arc
This is the meta reason, yes. And it has permeated the entire Post time skip
I think Oda realizes he would incapable of keeping up with exactly how strong anyone is if he gave them as many fights as Luffy across all the arcs
like for example you can’t answer how strong Dressrosa Zoro is because Oda can’t answer how strong Dressrosa Zoro is… Zoro just arrives in Wano and can suddenly fight A. YC1 with no clear explanation for how strong he was entering Wano to begin with… We are just supposed to be vaguely aware that Wano Zoro must have been Stronger than Dressrosa Zoro even though there’s no in-world reason for it… Only a meta reason
Oda can have Zoro or Sanji fight top tiers but it’s always as a form or hypetooling with no real drama behind it because the only time Oda has ever had a a climactic fight end with a main character losing was the Zoro vs Mihawk fight… Oda can’t have Dressrosa Zoro fight Fujitora in a real fight where Zoro just plainly loses because Oda doesn’t know how strong Dressrosa Zoro is and the big reason of course is… WHATS STOPPING DRESSROSA ZORO FROM JUST GETTING A POWER UP?
since we saw Luffy jump like 4 tiers to reason Kaido in Wano, why can’t Sanji just jump 4 tiers in Egghead to reach Kizaru?
this is the whole reason the strawhats must be so useless in arcs because Oda cannot justify their power levels if he has to actually demonstrate them outside of when the plot needs them