Interesting perspective, but 1984 machines would have all been incredibly tightly resource-constrained with very low resolution screens, making it difficult to even display two windows at once. Fair enough to question it in 1984 but times have changed!
Indeed, the article was focusing on a false dichotomy: either you must exit one application before using another (no windows), or your applications must be relegated to unusably small fractions of the screen (windows).
If you don't like either option, there's a third choice: run multiple applications, only show one at a time and allow fast switching between them.
Anyone remember DESQview? It allowed you to run multiple fullscreen text mode applications and switch between them by double-tapping the alt key. I used to run Telix and Wordperfect at the same time and could still get a DOS prompt if I needed one.