Thanks to Kalifornia's retrofitted buildings and roads, that quake in the Central part of the state lost 2 lives (sadly), not the 10's of thousands that usually succomb when a large (and 6.5 is a pretty big one) earthquake shakes buildings made of mud and sand.
Nope, it's mainly that San Simeon was in the middle of nowhere and Bam apparently took place in the center of a densely-populated small city.
If it had happened directly under downtown LA or San Jose or Berkeley, while it likely wouldn't have killed tens of thousands, we'd be talking about hundreds killed and a bigger economic disaster than 9/11.
People should not get overconfident. The Japanese were when looking at Loma Prieta and Northridge, prior to Kobe. They thought they were prepared and had this earthquake thing figured out, compared to those silly Americans. They didn't.