Again, i dont agree with the "title" statement at all and never have. If we can magically believe Blackbeard can surpass the WSC, then we can also believe that Shanks isn't bound to arbitrary powerscaling against the WSS, to whom he's never lost to and whom he's been portrayed as more important.
Again, these are the men Kaido respected and potentially feared:
Neither Mihawk or BB are on this list. And no need to tell me why, I've heard all of the reasoning for both and understand the logic, it's just not the point of this scene.