Florida vs California is telling. FL mostly stayed open and didn't do much worse than CA, despite Florida's much older population.
SF and LA are pretty dense in some areas, and not very car-friendly.
Florida skews heavily toward relatively well-off retiree who might already be a little more socially distanced than the norm.
CA: 253.9 residents per square mile
FL: 397.2 residents per square mile
What's more interesting is the local density; what does the distributions of residents per square miles looks like.