As a Rams fan, its a little disappointing to see the lukewarm LA turnout but theres good reasons for it:
1. The West Coast is the least devoted sports region in the Nation. Outside of a few select fanbases (raiders, dodgers, niners, lakers), they dont have the fervor about sports the way the Midwest, South and East Coast do. Its too laid back, too busy with outdoors/other events and too rational a region to have that irrational love of sports that other areas do.
2. The Rams have moved more than any other NFL franchise. Difficult to build roots that way. Doesnt help that they moved to Anaheim then to St. Louis right during the time LA was becoming a predominantly Mexican city. Its a lowkey thing to notice, but the most successful teams/fanbases in North America came to prominence when they got good during a cities boom period (Cowboys got good when Dallas boomed in the 70s, The U were good when Miami was becoming a intl glamour city, Warriors are good when the Bay/Silicon Valley is booming, Seahawks got good when Amazon turned Seattle into a boom town, etc, etc)
3. Rams havent been back long enough for a generation to grow up with them. But its getting better. I was surprised at the love they got when I saw the week 3 matchup against the Bucs at SoFI