I don't know what type of steel do you refer with super steel when you are speaking about axes, but you can fing pretty good steels in some head and a practical reason to use them or better ones in other heads. I will explain myself.
As Hacked has said you can find 5160 steel in Council Tool axes, you can also find L6 tool steel in a commercial but very expensive axe manufacturer, John Neeman, and unidentified tool steels in racing axes. Noone says what they use, but Keech uses a unidentified tool steel (those axes are very used in my country), Tuatahi says this in their website "hand forged from a block of the highest quality tool steel", Mike Osborne says this "Each axe starts out as a billet of high grade tool steel", Basque manufacturer Jauregi uses custom made steel close to a tool steel (I don't exactly know which) in his racing axes... As you can see there is a lot of secrecy, but there are more steels in the axe world apart of the 10XX or slightly modified 10XX steel families.
And there is a practical reason to use even better steels in the axes, there are axes made for anything more than chopping or splitting, carpenter axes. You don't have much demand of carpenter axes nowadays, but this is a unexplored world for tool or super steels. Those axes don't suffer so hard pounding, they are supposed to cut and any improvement in wear resistance would be a very good benefit for the carpenter. Any time he saves sharpening is a benefit of working time.
The same can be said about butcher axes, here hygienic laws say they have to be stainless. Any improvement you do to those axes would translate in business improvement.