"Email is 20 years old and has all of the same restrictions and quirks that it had when it was first used in 1993."
E-mail is much older than that. SMTP, the mail transfer protocol that's standard today, became widely used in the 1980s.[1] E-mail between machines on the ARPANET (the precursor of today's internet) dates back to 1971, and already used the "user@host" form at that time.[2]