The Cards have a very smart front office, one that restocks the farm system (most teams trade away their top prospects) and bases their team off of stats. They are able to consistently use the strategy featured in Moneyball, a stats first method, one that basis success off of not on how well a player "looks" or is scouted, but on how well he is able to perform on paper. This has been adopted by many teams in the majors, but only very few can do it well. Since the Cardinals have the money, they're able to get players that other teams can't get, while still being able to use a statistical way of decision making.
How else are the Cardinals winning games? RISP (runners in scoring position). Although that's been their thing this season, they actually lead the league in average with runners in scoring position over the past 10 years as well. With a .279 mark, the Cardinals rank first of thirty teams from 2004 to 2013 in the average with RISP category. When runners are in scoring position (on second or third base) the Cardinals are able to capitalize more then any other team, which ultimately gives them the best chance to win. Five Cardinals, Allen Craig (1st), Matt Carpenter (4th), Carlos Beltran (5th), Matt Holliday (6th), and Yadier Molina (9th), rank in the top 10 of batting average with RISP this year, yet another reason why they continue to score timely runs, and are able to win important games.
Why haven't more teams caught on? Using statistics will win you ballgames. For the teams who don't, they'll continue to wonder how this team beat them, or how that team beat them. People in baseball have made made evolutions to the game, and we should be going through one right now. The teams who use stats as the answer are truly one step ahead, and truly have better chances of winning the World Series, compared to the teams who continue to use old fashioned scouting as a way of life. If you don't believe me or think otherwise, read the article again. Because the Cardinals are showing that they've figured it out.