Well, you don't know that. There are states and countries that have not gone to "shelter-in-place" extremes and have been outperforming California.

New York is special in America. It's very dense, and every time you get on a subway train, which most of the city does every working day, you're sharing a cramped space with hundreds of random individuals. It's not hard to see why they've been hit harder than anywhere in the US.

To pretend the only possible difference is a binary distinction between lockdown or not is reductionist ad absurdum.