Pettis had been popular among western media and analyst circle for a while after the financial crisis due to his consistent bearish view on Chinese economy. He was popular because he had been a professor of finance in one of the China's best universities (Peking University) for many years and is considered to "understand China." Therefore he was supposed to be more insightful and credible than your run-of-the-mill western analysts and lend to the credibilty of "China collapse" or "China hard-landing" crowd in desperate need of such things. For example, he insisted that China's GDP growth rate would drop to 3% or lower after the stimulus measures implemented after the financial crisis were withdrawn or faded away.
I had followed his blog for a number of years after the 2008 financial crisis, and even debated with him occasionally. Eventually I stopped following because I found his arguments were rather simplistic and him a sort of one-trick pony. His arguments boiled down to the so-called account identity, that is the relationship between investment, consumption, and net export in national economy. He thought Chinese economy had substantial imbalances and suffered from lack of consumption. The export growth was not sustainable and investment was debt driven. So China would have to significantly increase consumption, which was not easy due to a series of factors, including political barriers and demographic trend. Since mathematically the accounting identity has to hold, therefore it follows that China's economy invariably will slow down drastically or falter. Most of his blog posts were rehashing the same arguments again and again at least during the time.
I have to say his arguments made some sense, but his view about existing imbalance in Chinese economy was not something particularly unique or insightful. Most economists, policy makers and indeed Chinese leadership knew the problem and have been tackling the problem in various ways. Again, what made Pettis stand out was not so much because of his "insight" than his being inside China and teaching at an elite Chinese university for years.
I won't go into too much details, but my counterarguments, very simply, was that his view was too mechanical based on some accounting identity, and he ignored and didn't quite understand the underlying dynamics of the Chinese economy. It's not like that the accounting identity was a Newton's law and it does not describe the cause-and-effect relationship (Pettis has an undergraduate degree in physics). Furthermore, the nature of debt in China was quite different from that in a lot of western countries. While the demographic dividends (人口红利) in China have been diminishing, the dividends from the vastly improved human capital (人才红利) have kept increasing. The rapid and large-scale innovation in China over the last decade have proved my point. After all, China was only a middle-income country back then, and still is an upper-middle income country. There are plenty of opportunities and room for growth.
Double the GDP in fifteen years? It would be a failure of gigantic proportion if China could not delivery that. Double the GDP in 15 years is no small feat for any large economy. For China, it would be an average scenario, even at this stage of the growth.
In my decades of experiences of reading, observing and interacting with western media, analysts and indeed ordinary westerners, I've found majority of them ignorant and arrogant about China. These ignorance and arrogance can sometimes turn into overly panic and pessimism when they realize China has made huge strides beyond their wildest dream/nightmare. When these are mixed with some stream of subconsciousness (or consciousness) of wishing China to fail or at least slow down, these people can fall easy prey to very simplistic views. It's not hard to find these type of people around you, even in this forum or indeed in this thread.