I agree ,S7 is better in big knives. The Swamp Warden was a fantastic little knife and made from a steel that is well suited for a knife that size. I personally think anything smaller than the MuttLY is not really an appropriate use for S7.

There are really no "better" cutlery steels just steels that are better at certain jobs. For example if you are a diver and need a knife to cut netting and line then 440C is perfect because it is more corrosion resistant than any other knife steel
and has decent edge retention. It would not be a great choice in a big chopper like the DF though.

INFI is so expansive because it has a LOT of pricey alloys that make it a good choice for almost every type of knife. It would be a waste of money and alloy in a knife that did not really need all those things though. Personally I think the Swamp Warden is a better knife than the more expensive INFI skelly warden.
Because of it's size and protective coating the Swarden does not need the corrosion resistance or toughness. What it does benifit from is edge retention and the 52100/SR101 steel in the Swarden is a bit better in that regard than INFI.

INFI is perfect in an hard use general purpose knife. I have the SS4 and have it sharpened to a much finer edge than you could normally get away with because INFI is tough enough not to chip. Also when it is the only knife on hand I will baton with it so that extra toughness is nice.

S7= big knives
52100= knives that need good edges
INFI = knives that NEED everything