knotslip, I don't think the two are really "inversely proportional"
take INFI for example...
unless of course you just mean within one knife...
in that case, yes I believe that's generally how it works... but I believe Mike Stewart once told me that most steels kind of have a "sweet spot" where the toughness to strength ratio are highest.

paraphrasing def. but I believe what he was basically telling me was along those lines.

That also brings up the fact that SR's are differentially hardened.
Then it gets pretty confusing.