Why Are Phishing Scams So Lame?

Maule points out the myriad flaws in a phishing scam he recently received in his e-mail in box. The low quality of the scam e-mail is typical. Why? One could have a much more polished scam e-mail with only a little effort, and presumably, it would catch more savvy recepients, dramatically increasing its yield. It isn't obvious that a better polished scam would be more easily traced. Someone sophisticated enough to conduct these scams should surely have the skill set to write better e-mails. Is this a case of predators deliberately choosing the dotty and the creduluous as victims in order to reduce the likelilihood that someone competent will be burned and in turn will devote serious attention to locating the perpetrators? Or are the perpetrators really just less sophisticated themselves than I give them credit for being?