From the limited amount of information in the news article, IMHO it's not reasonable to draw any conclusions regarding the efficacy (or lack thereof) of the .38Spl round.
- The article doesn't actually say that the round was indeed .38Spl; it could be one of the older and more anemic .38-caliber rounds like .38 S&W or even .38 Short Colt!
- As MKII correctly points out, not every head shot is fatal or even incapacitating. People need to forget all of those Hollywood head shots that result in a fountain of blood and instant incapacitation. How do we know that the BG wasn't barely grazed by the shots?
- The victim/shooter stopped the attack. The BG ran away. Sounds like successful home defense to me! Perhaps the brave lady is lucky that the man didn't press the attack, but she's better off lucky than dead.