One Piece started with Luffy promising Shanks He will surpass him one day, turning Shanks Level into an Endgame Destination for Luffy's Power Growth. Since then, Oda keeps Introducing Powerful Characters, which would automatically make Readers curious about how They compare to Shanks,
Regardless of where you Rank Shanks, and regardless of who you believe are Stronger or Weaker than him, the term I'm gonna use here is "Comparable". Meaning just because A is Stronger than B or Vice Versa, They can still be Comparable & within similar Pay Grade as long as Manga supports it,
Mihawk? He was Compared to Shanks
WB? He was Compared to Shanks
Kaidou? He was Compared to Shanks
Two DFs Blackbeard? He was Compared to Shanks
Emperors in General?
Admirals?
Roger? Rayleigh? Gaban? Oden?
Xebec? Old Gen in General?
It's like no matter who is Latest Hype, no matter which Powerful Character shows up, Oda still finds a way to compare them to Shanks, to insert in his reader's mind the idea that all these guys are still within Shanks Pay Grade, regardless of which one is Stronger,
The Problem is that even in Final Saga, Oda refuses to stop this!
Gorosei? Still Comparable to Shanks
Joy Boy? Even Joy Boy didn't survive Shanks Hype, Oda still compared them,
Then We reach Elbaph, and Oda is so persistent,
He continues to compare Shamrock to Shanks, and compare Loki to Shanks,
And with Reveal of Loki's Powers, this means Shanks is also comparable to Elbaph's God of War & his Rival Nika,