Static site generation is not a 'reaction' to client-side rendering
Static Site Generation came about as a solution to the maladies of SSR and CSR.
As someone who's website literally reads, Created: October 14, 1994 by Elf M. Sternberg, that line made me blink three times. I write stories, and there's no way I was going to convert them all to HTML by hand. From 1994 through to today, a total of 29 years, the story site has been statically generated from something resembling Markdown (for a while it was a format called Muse, which almost nobody remembers, and before that it was just called "Usenet emphasis style"), so static site generation can hardly be called "a reaction to server-side or client-side rendering."
It was literally the first thing we did. But the Eternal Amnesia means most people don't know that.