Probably mistaken. Only a mad can do so. At least if I could be the owner of G-Mail, I would just tell you that sorry I don't have money to store your deleted massage. Because I can store those things for which I'm getting money. As G-Mail is ad-supported free mail, I must store all your valid mails and show you as you login. But, what would I earn storing the deleted one? This is just common sense.
Some news stories have suggested that Google intends to keep copies of users' email messages even after they've deleted them, or closed their accounts. This is simply not true. Google keeps multiple backup copies of users' emails so that they can recover messages and restore accounts in case of errors or system failure. (Can you remember what happened when WC melt down?) Even if a message has been deleted or an account is no longer active, messages may remain on their backup systems for some period of time. This is standard practice in the email industry, which Gmail and other major webmail services follow in order to provide a reliable service for users. They will make reasonable efforts to remove deleted information from our systems as quickly as is practical.
But, why so many?
so delete e-mail isn't fully deleted for up to a month