The conference, which ends Friday, also reflected some new challenges facing China. It was held at the same time as another big event: a six-day import expo in Shanghai aimed at showing China as a big buyer of foreign goods. With American tariffs threatening to slow a weakening Chinese economy, the country’s leader, Xi Jinping, spoke at the expo on Monday to proclaim that China could be a positive force in global trade.

At Wuzhen, by contrast, Mr. Xi appeared only by proxy. The head of the Communist Party’s propaganda department, Huang Kunming, conveyed a message of thanks from Mr. Xi and then delivered an opening address that extolled the world-changing power of internet access.

Emissaries from Silicon Valley were also in short supply. Last year, the speakers at Wuzhen included Tim Cook, Apple’s chief executive, as well as Sundar Pichai of Google. This year, the sole Western tech executive to give a keynote address was Steve Mollenkopf, the chief executive of the chip maker Qualcomm.

His appearance served as a reminder of American companies’ continuing travails in China, which could deepen as the two powers wrestle over high-tech supremacy. Qualcomm scrapped a $44 billion deal to buy a Dutch chip manufacturer this year after China’s antitrust authorities declined to approve it, a move widely viewed as retaliation in the trade war.