Wikipedia refers to it as:
"The term hermit kingdom is used to refer to any country, organization or society which willfully walls itself off, either metaphorically or physically, from the rest of the world."
Seems reasonable.
China is going to become increasingly walled off in terms of physical access into China (and they'll likely further restrict foreign travel by their citizens), matching how they've already walled the country off with regards to the Internet & foreign press. It had to happen, the smothering process has to continue indefinitely until or unless they reverse course on liberalization. These processes tend to spiral down by necessity. The more you clamp down, the more you have to clamp down; you can't allow challenges to the vast number of invented narratives (which comes from foreign injection: outside press, outside visitors, allowing a large number of your citizens to visit other nations and see that the narratives are falsified, etc).
The exports would be the last thing to get walled off, I'd expect. Neither side of the wall really wants that. It's not hard to see a scenario where China is highly isolated socially and culturally, while still being an immense export power.
Now, compared to then, China has a huge internal market thanks to the rising of the middle class that could take the clash of a potential export collapse by leveraging their internal market.
So said, whenever there's somebody exporting there's another one importing. Perhaps we should ask ourselves where are we going to get the goods that now are produced largely in China.