Instead of lockdown, why don't Governments issue free Vitamin D to all households and at all pharamcies, all winter? The cost would be a few million - against tens of billions for lockdown.

Because vitamin might make a difference but it's won't be enough to just willy nilly let people catch covid at will without any precautions. IF it was basically a cure as you're implying then it would have been found out a long time ago as the difference would have been obvious even without a controlled experiment.

Because VitD might reduce mortality by 20% to pick a number, which without lockdown still leaves millions of Americans dead - while lockdowns aim to stop the exponential growth and (if adhered to) reduce the number of infections and deaths by 95%+...

They put it in milk and other products already just for health.

Does this include the cheap Vitamin-D3 that's commonly sold at Walgreens and supermarkets?

One of the tiny round capsules claims to have 2,000 IUs, which seems like a lot.

Dr. Fauci supposedly takes 6000 IU of Vitamin D daily.

https://vitamindwiki.com/Dr.+Fauci+takes+6%2C000+IU+of+Vitam...

yes

400 is recommended for dark winters, don't take more than 4000.

Source, UK NHS

https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-...

One could make a similar argument, but you then run up against a major WHO policy document on public health measures to combat influenza, which states:

"Ten RCTs were included in the meta-analysis, and there was no evidence that face masks are effective in reducing transmission of laboratory-confirmed influenza."

and

"According to the GRADE approach, there was moderate quality of evidence involving >6000 participants that face masks are ineffective in reducing influenza transmission in the community."

and

"Reusable cloth face masks are not recommended. Medical face masks are generally not reusable, and an adequate supply would be essential if the use of face masks was recommended. If worn by a symptomatic case, that person might require multiple masks per day for multiple days of illness."

https://www.who.int/influenza/publications/public_health_mea...

Good thing it's not an influenza pandemic