Hussar
Legend
Well, most individual campaigns don't cover timescales on which "technological" change of the setting would be visible.
The Forgotten Realms has been forced through several changes, as has the Dragonlance setting. The players always gripe about it, call it metaplot and evil moneygrubbing by the publisher.
Yes... and no.
I only bought Greyhawk materials in the way-back-when of my 1e days. Those materials mentioned the past of the setting in passng - whole cultures and peoples migrating, empires destroyed in rains of colorless fire. In the past, there were peoples with powers lost to the Greyhawk you were playing in.
Then they gave you the state of the world at a particular time. Evolving it forwards was then your own problem.
As I said above - players are conservative.
Well, sort of. Even in the prehistory cultures in Greyhawk, they're still pretty much middle ages technologically and culturally. There's no "stone age" or even "bronze age" in Greyhawk or Forgotten Realms.