I'm not sure about that honestly. At the extreme there's definitely COVID deniers who followed no precautions, but IME most "normal" people I know felt more comfortable spending time indoors with masks than they would have otherwise. And 6 feet is really not enough spacing in many indoor environments. With things like elevators the other person could be gone and you could still be exposing yourself.

There is also precedence for some of these statistics with Asian countries during the SARS pandemic, and in these places rule following is generally much better.

And with a smaller sample size there are some case studies from restaurant transmission. Staff seem to get infected less frequently than other diners, even though they are in the space for longer. There are a few possible explanations, but the fact that staff don't take their masks off is a pretty compelling one.