MonsterEnvy
Legend
There is also the simple fact that Evil rules half the globe. One of the points made when discussing D&D settings, is that the forces of evil are much more powerful in Greyhawk then most settings.
On the Vecna thing. While his ultimate plan to destroy the multiverse fails in Die Vecna Die. He still ends the adventure better off then before. (Despite the name of the adventure it's impossible for Vecna to actually die in it.) His plan fails and he is booted back to Greyhawk by the Lady of Pain, losing the power of a greater god and becoming a lesser god, and only succeeding in minorly changing how the universe works. (the 2e to 3e changes.) While this looks like a defeat, when the adventure starts Vecna is only a Demigod and is trapped in Ravenloft. At the end he is back in his home plan and has increased in power by becoming a lesser god.
On the Vecna thing. While his ultimate plan to destroy the multiverse fails in Die Vecna Die. He still ends the adventure better off then before. (Despite the name of the adventure it's impossible for Vecna to actually die in it.) His plan fails and he is booted back to Greyhawk by the Lady of Pain, losing the power of a greater god and becoming a lesser god, and only succeeding in minorly changing how the universe works. (the 2e to 3e changes.) While this looks like a defeat, when the adventure starts Vecna is only a Demigod and is trapped in Ravenloft. At the end he is back in his home plan and has increased in power by becoming a lesser god.