Just curious, what "enormous advantage" do the Cardinals have? That they drew over 3.5M fans to their ball park this year? Or that the organization consistently puts a competitive team on the field? That they can let the best player in the game walk, because they refuse to get stuck with overpaying a ridiculous contract, only to make it to the league championship series in each of the 3 seasons since they let him go?
Their payroll is a modest 13th in MLB, and their tv revenue is no where close to the top tier in the game, yet they have played in and won more playoff games in the past 5 years than any team in their sport. Is that the "enormous advantage" you speak of? Or is it something different?
And why do you seem to think that fans "overlook the Rams for losing and SHIFT their allegiance" to only the winning franchises? Just because they root hard for the teams (Cardinals and Blues) who have demonstrated consistently competitive teams doesn't mean they have shifted allegiance. It means they would rather support (financially and emotionally) teams that give them a return on that investment. And please don't think this is isolated to the STL market. It's the nature of sports and the sports fan. IMO it has nothing to do with being a fair weather fan.
I'm saying it aggravates me deeply when the comparison is drawn between the Cardinals and Rams. I will admit, the Cardinals have done very well for themselves but they do have an enormous advantage. Yes, they were 13th this year in total team payroll but that is a highly misleading figure when taken alone. Some teams listed above the Cardinals in salary spending only payed out less than 1% more. Now looking back over the past 30 years, the Cardinals have been consistently in the top 10 with their salary spendings.
However, this doesn't explain completely why the Cardinals have done so well. Looking at the National League Central division, the Cardinals have almost always paid more than the Pirates, Reds, Brewers, and Cubs so it should be noted that they have an advantage to make the playoffs every year. The Reds did have the higher salary this year (by less than 1%) but the Cardinals gain the advantage in one of the best, more highly paid coaching staffs in the MLB.
Now let's add the fact that the Cardinals play in the National league. The majority of the top 10 most highly paid teams are in the American league (this includes 4 of the top 6). Therefore, the Cardinals have to play these teams less often and are not competing with any of them for a playoff spot unless they fall in their own division. When the playoffs come around, some of these top teams who share a division are forced into a deadly one game wild card playoff matchup. Once you examine all this, you find that the Nationals and the Cardinals have the easiest paths to the World Series.
Say what you will about baseball but it is plainly unfair. The Yankees have paid the most in net salary in MLB history and they have won 27 times. Teams like the Padres, Rockies, Brewers, Astros, Rays, and Mariners (all lower paid teams) have never won. Obviously salary is a huge factor.