You don't know that.
it's the distancing that's doing the work of "much less coronavirus". for your statement to be relatively true, we'd need to live in a world with no lockdowns and no distancing.
> The findings of this systematic review and meta-analysis support physical distancing of 1 m or more and provide quantitative estimates for models and contact tracing to inform policy. Optimum use of face masks, respirators, and eye protection in public and health-care settings should be informed by these findings and contextual factors. Robust randomised trials are needed to better inform the evidence for these interventions, but this systematic appraisal of currently best available evidence might inform interim guidance.
This is clear: physical distance definitely works. Optimal use of masks might work -- that's all they can say, and they need better evidence.
And I feel like we can reason about this to some extent from first principles - If the virus is spread through particles from faces, then face coverings will decrease the numbers of particles from faces that 1) get into the air and 2) get into peoples' faces, no matter how crappy the face coverings are. It seems more plausible to me that the problem is lack of data rather than incorrect conclusion, which seems like a reasonable interpretation of this particular study?
> * most masks provide marginal protection to the wearer
> * the masks that provide effective protection should be saved for those in situations where they need them (and can be knowledgeably used)
> * most people probably don't need those masks"
yup, moreover, masks are marginal on top of other measures, most notably distancing. masks can make a difference if you're in a situation where you can't distance when face-to-face in proximity of strangers for more than a short time. distancing requires less "expertise" and cognizance as well, so is a better principal measure all around.
that's a more nuanced message than "masks don't work". the opposing "wear masks at all times" is similarly dogmatic and incorrect.