It was not Mao chose to isolate China from the world. It was China was isolated by the US led wrold. You know Chairman Mao nationalized all the properties owned by foreigners to protect China being 蚕食 by foreigners. I think China probably deserved the punishment of isolation since Chairman mao took away foreigners share of China.

As for 自己古代文明, there are so many ancient books around, it was never be a problem to communicate with our ancestors. It was a period of reflecting of ancient culture.

None of these problem is no important than the nuclear bomb that Mao gave us.