https://www.bloomberg.com/news/articles/2021-05-11/the-business-case-for-car-free-streets

It's really common sense. In cities, especially NYC, where walking is the primary means of transportation, the vast majority of business comes from foot traffic. Cars are loud and unpleasant to be around, meaning people are less likely to hang out when they're nearby. Remove the cars, and all of a sudden you have a lot more foot traffic. Look at places like Meatpacking now vs 5-10 years ago. Or Broadway, 14th Street, etc. All have far more foot traffic than before and business revenues are much better compared to nearby businesses on car-centric streets.

People in cars don't stop into places unplanned. They go directly to their destination, get what they need, and leave, usually never noticing any of the businesses they pass on the way, so they'll never know to even go to those places, let alone stop at them on the way to somewhere else.