full circle?
the irony indeed.
I've never seen any added javascript to a page that went as far as generating and rendering other pages completely, that's always been a refresh. If it's not then that's literally the same thing as a SPA, and is actually isomorphic javascript.
The "sprinkled javascript" that your talking about was basically used to do some simple DOM manipulation and a few XHR requests. It is not the same as a full single page app that is bootstrapped from server-side markup.
pjax[1] does what you are describing. There are other similar libraries as well. On user navigation, it makes a XHR request to the server, and updates in place any changed DOM elements. I like this, because it progressively enhances the user experience. An application should focus on serving content quickly to the user, then improving the experience where browsers leave a gap. Notice that pjax provides the same functionality as an isomorphic javascript without inflicting upon the world server side javascript ;)
That said, this project was created in February 2015... It's not that the "Traditional server-rendered pages" approach had been doing this for decades and isomorophic javascript simply reinvented the wheel here... this is a new project.
I shouldn't have claimed that you need full javascript to do this, that was clearly wrong, but my point is that isomorophic javascript is not the same as the common traditional server-rendered pages used before javascript single page applications came around.
But in my particular case the websites need to be server-side for SEO, so it's mostly just that I want to use React for reusability and because I prefer it over wordpress theming with php tags.
Furthermore, I can now use React and still deploy the site on a typical LAMP-stack cheap hosting!