@discographer-- Although I agree with you that archetypes are frequently used for short story characterization, I don't think that they're always necessary.
Usually, short stories have only several main characters. The supporting characters do not have to be described in detail and are usually only mentioned. Such as the waitress or the mailman as the article described. The main characters are the only ones that need to be described and explained in more detail because the reader needs to understand their personality and the reasons for why they do things. So it's not very difficult to develop those few characters.