Hotmail was already the easy-mode stuff.

Before that you'd get your email account provided by the ISP, and before that you'd have to find someone who ran an email server and ask nicely for them to make you an account.

And regarding ease of use: The reason why e.g. SMTP is human-readable is because in the early days SMTP wasn't the protocol that your email client used to talk to the server. It was the email client.

You'd just telnet to your server and type in the SMTP commands manually.