Those "announced attendance" numbers can be misleading. For this series, I'd wager that the percentage of people who actually attended the game was much higher than other games when the announced attendance is greater. This was a weekday series instead of a weekend series. Weekday series attract smaller crowds. The time of the year and the weather, I'll bet, had an influence.
It's the casual fans that pump up the attendance in all baseball cities though and this series, for some reason, didn't attract the casual fans.