While we may pay lip service to the web as "open" and "international", it's pretty western and particularly US dominated. From basic infrastructure like core domain names, to standards bodies like the W3C and IEEE, to the big companies like Google, Facebook, Ebay, PayPal, Anazon, Apple and co.
Even sites like Wikipedia, supposedly available to anyone to edit, are pretty much dominated by specific points of view and ideas (even if sometimes those who held those like to think that those ideas are or should be universal and/or neutral).
Neither economically, nor culturally does it make sense for a nation the size of China (or even for EU, but I digres) to participate in such a web. They are not some pushover country that was created a century ago. They have their own, millenia old, civilization. It's not like they are isolated by doing the firewall thing either. They get all the good (and the crap) we get in large does anyway, from the Kardasians to Jackson Pollock.
Think experiment: if the internet was mostly run and dominated by USSR, including a "neutral" Commipedia full of USSR points of view and material, would the US adopt it? Or would they build their own counterpart?