The problem that broadly there are two groups, the “get on with it” and the “cautious” (and yes, I appreciate it’s a spectrum). Current policy (or lack of) on mask wearing in England gives us the worst of all worlds with both groups.
a) the “get on with it” group are taking advantage of freedoms, but with no culture of mask wearing, many are acting as though Covid is history and behaving in ways that will only lead to a resurgence (ie thread about some hairdressers already not bothering only a week or so in,despite prolonged close contact). That risks repeating what’s happening in Texas and Florida.... which would be bad for business and bad for health. Mandatory mask wearing would reduce more risky behaviours brought about by those who think “it’s all over” (though wouldn’t eliminate - there will always be some who will disregard it) the potential for this the double whammy hit to business and health that’s occurring in the USA at the moment.
b) the “cautious” group (which I think is actually the silent majority based on polls on mask wearing) who are minimising going out, often because they don’t want to encounter the “get on with it” group who aren’t taking any precautions whatsoever barging in/standing close etc. That’s very bad for business. If masks were mandatory, that fear would be alleviated... not in all, but in many, and footfall would increase.
So, all in all, irrespective of whether the risk in a shop is particularly significant risk, mask wearing would help significantly i think.
Of course there are those who say in a strop “that’s it, I won’t go shopping any more then!”.... but give them a fortnight and they will like everyone else.