I've wondered if this creates an unintentional selection process, even if the scammers aren't aware of how it works. Like, if the linked paper is correct, then the most successful scamming strategies involving Nigerian princes etc. propagate among the Nigerian scamming community (even if they were originally created by a complete moron), while the people painstakingly crafting believable scam emails end up with worse results and either leave the scamming trade or adopt the email format of a more successful acquaintance.