> However, its also important to mention, that with react and careful planing, a no-js version is basically included for free.

Careful planning is required of all frameworks to make a JS free version. I wouldn't say it's a feature of React or that it's free.

> One might debate if a page really needs hundreds of kb of js to function, but then again, this is not much different than the classical progressive enhancement site with jquery

JQuery was a crutch that wasn't strictly necessary and with modern browsers you can largely do without it and write pure JavaScript. Assuming you know how, which I would wager most developers don't.