Dan I thought your graphic is really good, it explains very well why social distancing is helpful. To reduce the contagion means 'flattening the curve,' as Tink mentions so not everyone gets sick at once and the health care system can cope.
During WWI and the Spanish flu, the single most helpful factor in recovery was quality of nursing care; and now in 2020 pandemic we must do everything possible so every sick person has the very best chance to recover.
Here is a video from a channel I found, this health care professional in UK is giving the latest information from all over the world plus the results of research published in medical journals like LANCET.
This information from this morning he is saying that one meter (three feet) social distancing is too short, we need to try for six feet I notice your chart is based on 1.5 metres but I have been doing only 3: