Comment by afiori

If you are referring to how SSR pages need to download the serialised page "props" and not just the html+js then good news! Solid 2.0 is about to solve this.

If you are referring to having to download react itself then you have to download the WebComponents code too.

Actually with smart use of forms and links you could make a js free react page (using forms to submit state changes) more easily than for WebComponents