Of those that were snake-bitten, were any without access to the offered cure?
John 3:14, Numbers 21:8-9.
Was being snake-bitten something they did? Or was it their condition of impending death by something externally inflicted?
Did everyone have access? Apparently not, since only those who believed accessed the healing. Faith (the noun; the thing believed) was required, and it came from hearing (the noun; the thing heard).
You presume it was the ultimate act of man looking that saved them, when it was the thing heard, which was the thing thought and spoken about by God. It was the Word alone that saved them. Their looking was merely their inevitable obedience.
No thing thought and spoken about by God? No healing.
No thing heard? No healing.
No thing believed? No healing.
Looking was not what healed them. Human action never saves, including whatever we think and speak about by our own word/s.
A Greek-thinking/speaking audience would have understood this on at least the minimal level of faith to give them access into the grace.
THAT is the Good News. Man effecting his own salvation by even one work himself is NOT.