That could be, but I'd rather they made the case. When SMTP came out, it was indeed very simple. In college in the 1980s, I could send email just by doing something like:

  % telnet mail.umich.edu 25

  MAIL FROM: <william@umich.edu>

  RCPT TO: <joe.blow@umich.edu>

  DATA

  From: William Pietri <william@umich.edu>
  To: My Skeptical Friend <joe.blow@umich.edu>
  Subject: Who needs a mail client?

  You can send email without a mail client!

  .

It's harder now, because spammers. But to me it's amazing that something like has been working for nearly 40 years. For perspective, it came out the same year as the Commodore 64.

The curious can read the inital RFC: https://tools.ietf.org/html/rfc821