AT&T Investing Lots In Network Upgrades, But Where?

Today's Business Journal notes that AT&T has already invested $1.1 billion this year to upgrade wireless (and wired) networks across California, which has included 100 new cell sites, 25 antennas in "high-traffic areas," and 35 separate 3G upgrades. So how come we couldn't get the internet to work on our iPhone all Labor Day weekend long? [SFBJ]