I have been thinking very hard about how important setting is in TTRPG’s. I used to think that setting was important but as my understanding has developed; it is clear to me that setting is the most important element of an RPG.
Rich engaging settings have dedicated audiences. Generic game systems have their fans. But even the fan of a specific system will jump ship if their favorite setting goes to a different system. Take for example Star Wars. There have been three different RPG systems utilized for Star Wars. Each of those systems has been very different mechanically but still maintained a following.
Star Trek RPG’s is an even more striking example. There have been SEVEN different systems built or adapted to Star Trek since 1978! There are several more if you count the GURPS and D20 versions. It’s likely someone has done a Savage Worlds or Powered by The Apocalypse variation for their home games.
There have been a variety of Marvel super hero games. Forgotten Realms has survived five different editions of D&D. The 1920’s world of HP Lovecraft’s cosmic horror is played in numerous very different game systems. Add to this the number of board games, computer games, films, books, TV series in these settings and clearly, the setting is of primary importance.
This particular set of examples solidifies, in my mind, the preeminence of the game masters efforts in world building. It’s more important than the choice of system. The choice of system does matter greatly. The way that it matters is that the system cannot conflict with the fictional themes and narratives of the setting. If the game mechanics conflict with the players conceptual understanding of how a light saber or the force works, then your Star Wars game is broken. As long as the player’s conceptual ideas of the setting match the mechanical representation of the game then you are good.
Certain systems do have their devotees but very rare is the fan who will play in any setting as long as you are playing GURPS/Savage Worlds/BRP/D6/D20. Much more common is the fan who will play any system set in a particular setting. To me, this very clearly establishes the primacy of world building in an RPG.