except the bit about them being the first professional sports team in the west. If I'm not mistaken the Los Angeles Dons of the AFL began at the same time in the Coliseum as the Rams. Believe it or not I was a Don fan until they folded. Then I attended Dorsey H.S. where the nickname was the "Dons". And the Niners did come into existence in San Francisco at the same time as the "Los Angeles" Rams. Moreover, the Los Angeles Angels had been playing professional baseball in the Pacific Coast League for many years before 1958-going back as far as the 30s if I'm correct.
Your right about how we have to get over the fact that this area is unique in their fandom. Ironically, its a GREAT NFL city given the many fans here who support just about every NFL franchise. It's just not one sided like most NFL cities.