Like it or not, the GFW helped to created the "most dramatic periods of economic development" in Chinese history.
Back in 2010, when Google chose to exit China, many argued the exact same that China is isolating itself from the outside. Such feeling is understandable from a western point of view, I mean for anyone from a western background there is simply no Internet if google/twitter/fb etc. are all unavailable. However, a bold however, 7 years after Google's exit from China, it has been proved again and again that the biggest motivation of GFW is the protectionism aiming to help domestic Internet companies - and that actually paid off pretty well.
You don't need Google/fb/twitter etc to have booming Internet/high tech economy. Look at China's social media, online payment, e-commerce, online gaming, AI, shared economy etc, did China miss out. Let me give you a bloody simple number: I didn't use any cash or bank card/credit card in the last 45 days, everything, I mean 100% everything, was paid by mobile.
This is not about some cheap nationalism - it is _all_ about how many good paying jobs can be made available in China for Chinese. It is the exact same as the Making America Great Again crap. Blocking google/fb/twitter was the first essential step to achieve that.