"Part of that will be logistical. It's just really hard, for example, to rebuild global supply chains or open them up," Garrett said, noting that reopening the economy will be a gradual process.
"But I think the bigger element is psychological. People are going to have to be confident enough to go back to live the daily lives. And I think that's just going to take some time," he said.
When asked about the major challenges for the global economy, the Wharton dean said "the fact that demand has collapsed in this economic hibernation is just a profound thing." However, that demand could come back, he added.
Another key challenge, Garrett believes, is that good businesses could go bankrupt because of a lack of revenue, and government bailouts are not unlimited. "I think that would slow the recovery," he said.
Despite the overall gloomy picture, Garrett has seen a silver lining. "The two obvious things to say, that technology and healthcare companies will do well coming out of the crisis," he said, noting that NASDAQ, a U.S. stock index powered by big tech companies, is actually up for the year.
Beyond that, Garrett highlighted the potential for the finance sector, saying that the world of private equity, hedge funds and venture capital will "probably boom" during the pandemic as they did after the global financial crisis.
Looking back to the period after the 2008 financial crisis, Garrett said major governments, including China, the United States and Britain, had taken enormous action in response to the crisis, and also had lots of collaboration and coordination mostly through the Group of 20.
"I think that kind of international collaboration has just been absent so far in response to the pandemic. And I hope we can change that," said Garrett, noting that each country's fiscal and monetary stimulus, though strong and appropriate, has a national and inward-looking focus.
"It's understandable for governments to want to use national policy tools to affect the national economy. But if they can do that in a way that promotes international coordination and international openness, that's a better way to go," he said.