There is no city I am aware of that seems to have the amount of parks and green space it wants. This paucity is particularly glaring when it comes to parks for children and most prevalent in large, dense urban areas. And this is why non-profits like San Francisco's City Fields Foundation are stepping in to upgrade existing parks because public funds are not available in the quantities demanded by the public.
On Saturday in San Francisco, the group held a ribbon-cutting for three refurbished soccer fields in the Crocker-Amazon neighborhood. The new fields will add approximately 12,358 hours of playtime on the soccer fields per year.
In Great Britain, the National Playing Fields Association has been doing this for over 70 years. Just goes to remind you, that when it comes to building any sort of infrastructure, there seems to be a great organizational advantage to having some sort of centralized body.