Isn't all that massive mid/new gen upscale?
These guys really "only" have their haki going on for them, while guys like Kuzan, Dragon and Sakazuki will likely nearly rival them in that as it seems, while they will also have top10 awakened s-class DF fruits.
Like no chance for example that Kuzan vs Garp crates 10times the visuals young Roger vs Garp created while using CoC, if Kuzan and Garp were not using CoC coating there aswell. By extension Akainu's eating good aswell ofc.
And it's also not the case that they are not as unique. Kuzan clearly adopted parts of Garp's fighting style, Dragon likely created the dragon claw style and who knows what's up with Akainu.
For all I know he might be top tier Katakuri, where he cannot be hit, even though he's a tank.
I love the OGs and everything about them is straight 10/10, but more and more I think we are in for a lot of high top tiers in the future.
Also fits that final saga doublespread, hence their narrative worth, and Oda's commentary saying Akainu would have gotten the OP in a year.