3.60 would do next to nothing, the key geohot released is basically PS3's root key, they use it to check if code is signed etc.
It is impossible to change because it was hardcoded into the PS3, if they change the key, all games made in the passed based on the current key would not work I assume and sony would be 10 feet under in law suits.
3.60 could DELAY what's going on now but there is nothing that can be done to permanently stop the custom firmware.
As always people will be silly enough to update their PS3 then complain everywhere on the interwebz about their own doing.