I can buy the «substantial outside investment» part, but the CCP got lots of help from the USSR, and frankly, the USA's side was the least immoral side during the Cold war, so if the CCP were more moral they could easily have gotten help from there instead of from the USSR.
What I do not buy is the ridiculous argument that just because a political entity is bigger, therefore it is harder to do anything! It's not true that democracy in the US must be worse than in Norway just because the US is a bigger country! It is not true that Romania is more corrupt than Iceland just because it is a bigger country! And it is not true that just because mainland China is bigger than the island of Taiwan it is harder to industrialise it!
More land and more people does mean more to do, but it also means more resources and more people to do it!