//Why did infections fall dramatically in the Spring lockdown when masks weren't even required?//
Because the fuller lockdown was effective, social distancing was introduced and large groups of employees worked from home, schools were shut and the weather was warmer....and quite a few people wore masks even tho the were'nt compulsory at that time.
When masks were made 'a requirement' on public transport and shops infections fell even further over the summer through to September. Masks may of been a factor but probably more was down to social distancing, school closures, testing, track and trace and the warm weather and people spending more time in fresh air outside or with open windows.
Whether we'er convinced by masks does'nt matter (my view is there of limited use genrally and of no use if people wear dirty masks day in day out or use them as an excuse to ignore distancing).... but am wearing one whenever there required because thats the advice and rule and we should all play are part in this effort and not endanger others just because we think we know better than the experts.
One suggestion is scientists should give more advice on how to choose and use a mask. Maybe adverts are needed.