I do not think he is deluded, he could be just flat out wrong.
There are counter points to his points. Briefly, we can say this.
1. Re: convergence. The point here is that that there is no law for convergence in economics, otherwise India will be a superpower like yesterday. The point is that he does not know when that Chinese economic miracle will slow down or stop. It could be the next 5 years, or the next 100 years, he does not know. It is not about convergence, it is about momentum, and does the PRC have the ability in them to keep the momentum going. So far, so good.
2. The Plaza Accord triggered the collapse of the property bubble and stock market bubble in Japan that had to be a contributing factor to the deflation the Japan is still fighting. Maybe they have some inflation now, but that deflation over two decades was economically debilitating if you ask me. The Plaza Accord, which readjusted the values of the Yen and USD to the liking of the Americans, probably was the trigger for the debt deflation scenario that Japan experienced. Unless there is a debt deflation scenario awaiting China, then Pettis is barking up the wrong tree in his objections.
3. Re: tech ... it could be that China today is more advanced than Japan in tech back then. China got lucky too, because of this precise time in history, Chinese technological powers have risen, and it is riding a new change in economics and technology, in other words, this 4th industrial revolution. When Japan was rising, the world was set in its way in the Cold War. In China's rise, we saw the interent revolution now the incoming 4th industrial revolution. China is leading the way with the 5G which is suppose to enable this 4th industrial revolution. Seems that China has a real advantage today in its rise compared to Japan back in the day, because Chinese tech today will be riding up on a revolutionary period, whereas the era Japan rose was less dramatic. Since China is spearheading this 5G revolution, that surely should be another growth driver that was not available to Japan back then.
4. Lastly, he brings out how similar were the trajectory of Japan's miracle and China's rise, regarding investment driven growth, income disparity, debt levels, blah blah blah. All I have to say to that is that are not automatic outcomes. That is the difference between the CCP and this guy in the ivory tower. They are both driving car. CCP looks ahead to the future. Pettis looks at the rear view mirror to drive forward. That is an expression from Wall Street, not the ivory tower. Instinctively, we know who is more likely to be right and more successful in their prognostications.