Comment by bflesch

Your suggestion sounds a bit detached from reality of many people.

In many countries it is physically impossible to get enough vitamin D from the sun, even if you go out naked.

Also did you ever notice that the cheap apartments in many places are facing north and do not have a balcony, and of course do not have a private garden? Now you are reduced to going to a park which in the "cheap" areas is also not a good spot to chill for 30 minutes.