I know SF's biggest rivals used to be the LA Rams, and later the Cowboys,but it seems like anywhere you read, SF Fans seem to truly hate Seattle Fans and the Seahawks. They don't really seem to care about the Rams or Cards (and this has been consistent IMO for awhile and not just as we have emerged this season as the top threat to their division supremecy). So are we locked and loaded as their main rival? Is it just Carroll/Harbaugh? Did they just come to hate us during the mid 2000's when we owned the NFCW? Will they revert back when the Rams become more competitive (especially if they eventually end up back in LA)?
On a related, but not really note, It seems like we have never had an exclusive true rival. I think Arizona is in the same boat, and if maybe the Holmgren/Hass heydays could have overlapped more with Warner's best years in AZ we could have established this.