The issue is that infections are not going to be evenly distributed inline with ICU beds. For example, NYC has 3,000 ICU beds, of which 80% are already occupied (65 by coronavirus patients based on the latest numbers). Meaning there are 600 ICU beds open right now. With a 10% ICU rate, that's only 6,000 confirmed infections in a city of 8.6M for the hospitals to be overwhelmed.