Can Spammers Really Spell Well?

I know that the sheer number of commercially driven spam mail is a reflection of the extremely low cost of sending them relative to the possibility that a substantial gain will ensue from a limited number. I have kept count over the last few days and think that I receive between 4 to 5 spam messages daily. I could therefore not help noting that there are defining characteristics of the spam that I receive. The first is that spam mail appears to be replete with grammatical errors and spelling mistakes. The other is that the application of the correct pronoun is often wrong. My main question then is that if one expects an average person to be taken in by the possibility of earning 25% of US$ 25 million, wouldn’t that recipient be particularly suspicious of the large number of errors in that single e-mail? Perhaps this is the wrong question because it appears that the indubitable negligence does not affect the overall success rate. If it did, then I guess that some spammers would take the time to run the messages through some person or computer facility that could detect and clean out the most obvious errors. Finally, it could just be that a person led to share a portion of US$ 25 million just has little time to conduct a spell check and write correct grammar.