[m-r-a-m]

The author only mentioned emails written in the last week (from the date of the article).

From the Gmail help site: "Please be aware, residual copies of deleted messages and accounts may take up to 60 days to be deleted from our active servers and may remain in our backup systems for an additional period of time." [1]

I assume that previous versions (auto-saved) of emails are treated as deleted emails and are removed after 60 days, but I can't find any documentation for this.

[1] https://support.google.com/mail/answer/7401?hl=en