If Yonkou>Admirals and Mihawk>Shanks, why do the Marines barely care about Mihawk?

The Marines barely cared about Mihawk at Marineford. They also replaced him with Seraphim, who can't even damage Sanji.

But we also know that (old) Yonkou>Admirals (see Greenbull afraid of Kaido and Shanks).

If Shanks is at least as strong as the other Yonkou (one shot Kidd) and Mihawk>Shanks, Mihawk should be considerably stronger than the Admirals.

And yet the Admirals are treated as the Marines' ultimate weapon, whereas Mihawk... is just there. How does that make any sense?

It's not because he doesn't have a crew because all the Yonkou and Admirals are super strong solo and losing Aokiji (solo) was seen as a huge loss. If Mihawk>Shanks>Admirals, again, why does nobody care about Mihawk?