Emails today are like automobiles from say, 1915 to 1920 or so. The design hearkened back to the shape of a carriage made to be pulled by horses.
Except for the subject line, an email is still shaped like a physical letter. If the “sender” field contains your name, why add a letter-like closing? If the email is delivered to an addressee, why is there a need for a salutation? In the 12th century, salutations were long and complicated, but by the 19th they had become formulaic and meaningless–unless a variation from the norm was a specific effort to convey a special meaning.
Drop the date, salutation and closing. They are not needed. By the time automobile design reached the 30’s and 40’s, the need to mimic the design of the horse-drawn carriage was fading fast and by the 50’s was gone entirely.
Perhaps we’ll see similar innovations in the future.