I don't know my history well enough to answer your question, but you can see one approach to the 1970s computing experience in this excellent video series about the Altair 8800 by deramp5113 on YouTube: https://www.youtube.com/playlist?list=PLB3mwSROoJ4KLWM8KwK0c...

There were fullscreen editors. You can see one with a 1978 copyright date at about 14:45 in this video: https://www.youtube.com/watch?v=YQNHg1XuFR4