Why can't I save draft in contact email?
I think you are correct that this functionality is missing. Workarounds that might serve you well include:


writing and saving the draft as a meeting note for the contact, then copy-pasting into an actual email when ready.
creating a new activity type that is called "email draft" and doing the same.
using an actual email client, such as gmail, to write and save a draft, and when ready, send, bccing civiemails so that the email is logged in the contact's activity. (this will require setup of email-to-activity if it hasn't already been configured)


I hope one of these helps!