[jasode]

>My understanding is that the author is saying you could build google docs to go from one state to another by submitting a form and doing server side rendering [...] This is obviously much worse user experience and way less efficient,

Your interpretation of "much worse user experience" is the opposite of the "work well!" that the author is claiming:

>Every single core function of these apps could work—and work well!—without a single drop of JavaScript.

https://gomakethings.com/the-web-is-mostly-links-and-forms/#....