I imagine the changes included steel availabilty, input from us and cost. I for one thought the knife did not have sod chopping ability.
you never know, maybe other testers suggested a saber grind to add weight or because the pried with it like crazy??
I am sure I am wrong but I think that only the scrap yard team knows what led to the changes.

the sod was 120
I imagine the regulator cost a lot more to manufacture. I am not sure if the stell is more expensive but the full flat grind and differtial heat treat would be more tike consuming and thus cost more. I have also heard the 52100 is much harder to work with. busse has obviously got that down but they may still be using more expensive methods to manufature these blades than sr77.