I love the rationalization people have to use to explain China's economic success. If what Deng brought was capitalism, then Obama is an anarcho-libertarian.
What was behind China's economic success then? (not snark, genuinely interested in hearing your thoughts)
As far as I know Deng did advocate a more open and free policy when it came to the markets, not in very concrete terms but certainly in veiled terms like "pragmatism" and "we must do whatever works" [1]. I'm not saying Deng made China a Randian libertarian's wet-dream but it seems he did push for free markets a little bit.
What was behind China's economic success then? (not snark, genuinely interested in hearing your thoughts)
Imitating the free-enterprise model of Hong Kong and Taiwan, decades after those territories had far outpaced China in prosperity. And one of the great advantages China has enjoyed in economic development, as compared to several other territories, is the large number of people who can communicate in local languages (various forms of Chinese) but who grew up without communist influences on their primary and secondary education. "Compatriots" from Taiwan and Hong Kong, and also "overseas Chinese" from many places in southeast Asia played a crucial role in boosting China's economic growth through direct investment after the beginnings of system reform in 1978. (Basis of knowledge: I began studying Chinese during the Cultural Revolution, and have met quite a few people from outside China who have invested over there, after investment began to be permitted.)
"Capitalism" means private ownership of capital. 30% of industrial and service sector assets in China are stated-owned: http://blogs.worldbank.org/eastasiapacific/state-owned-enter.... About 45% of the industrial sector is state-owned, down from 70% in 1999 (still more than two decades after Deng left office, and more than a decade after China's economic boom began). The profit share of the state owned enterprises is even higher: 43% of industrial and business profits in China yield from state owned enterprises: http://thediplomat.com/2013/06/19/reforming-chinas-state-own....
In a purely definitional sense, China is at best a hybrid economy now, and was a primarily communist economy long after its economy started booming.
Even to the extent that China's economy is ostensibly privately owned, the government still exercises tremendous control. For example while the banks are joint stock companies, and thus reflect substantial private ownership of equity, the Chinese government still owns the majority of the shares in many of them giving them tremendous power over those banks.
I don't think China can be fairly called a "capitalist" economy. It's a managed economy where the managers have allowed the free market to allocate resources at the lower levels, while the central government directs broader, longer-term economic objectives.
Time frame is an essential factor for assessing if it's a success. In 5 years? 10 year? 20 years? 50 years? What if the previous level was actually very high, say 50%, and the job was to increase from the low level 10% to 15%? With different time frames for evaluation, even someone do not have in-depth knowledge of a topic, she/he could still have some facts to raise valuable questions which can lead to an answer closer to the truth, if there is any we can find eventually. Sorry to not answer your question directly, but I think a different angle might be a better start point.