This post was edited by tenderloin at 2018-12-10 07:59
During qing empire period, China closed doors to the west and fell behind technologically and couldn't deal with western forces.
But all changed now because of the internet.
If China close doors to US and countries supporting US by shunting Huawei and ZTE over 5G, China still on the path of advancing technologically because of the internet. It will find the necessary information it needed.
So nothing to fear about isolations and backwards if China close doors to US and it's allies
During qing empire period, China closed doors to the west and fell behind technologically and couldn't deal with western forces
That fall-back was insignificant in comparison to the fall-back caused by first half of communist rule. During Qing period, western world wasn't that developed either. Things started to happen only after WW2.
nothing to fear about isolations and backwards if China close doors to US and it's allies
That depends on who you are talking about. China's leaders have clearly said that China does not only want to develop internally and grow economically, but also build it's international image and reputation.
For those aspirations, it will be a loss (of face if nothing more), even if China can develop everything it needs internally.
It is not only about technological development, but interaction between countries and enterprises, where currency is the instrument of exchange.
If Chinese companies cannot bring foreign currency from US-allied western markets, China still needs to make settlements to those open for China in currencies other than RMB (read USD). Not every country is ready to accept RMB, especially if those countries cannot trade in RMB with their US allies.
This means that China's foreign reserves will shrink dramatically, and China can forget about internationalizing RMB.
It would spell increased costs to everything related to OBOR, while at same time western countries are bulding their own implementations similar to OBOR to offer.
Closing the door is not a very smart move; it is also contrary to China's position of opening up and interacting more with the rest of the world, as announced by President Xi in international meetings. You don't have to shut your doors to deal with your enemies; you should be able to take them on at their own game!