Experts are often wrong. No one predicted the 2008 recession except for a few. 90% of the cases are in four countries. The virulence seems to be decreasing in China, the worse hit, which only had about 80K cases.
Yes, experts are often wrong and they err more often on the optimistic side.
90% of the cases in four countries is just the latest snapshot. As of now, there are 8 countries with more than 1,000 Covid-19 cases and 122 affected countries with 125,000 infections and 4,600 deaths.
Compared to 2003 SARS with a couple of dozens countries there were 8,098 infections in total and 774 deaths. Now, just Italy has more cases and deaths. A month ago, they had just a few cases - "nothing to worry about".
The Chinese after their initial bungling and cover up acted decisively. Building two new hospitals in 2 weeks seems like a good way to prevent the outbreak. Try that in New York.