From a reader:

One of the more interesting things I’ve learned thus far in college was learnt last summer during my golf class (PSU requires students to take two “gym” classes for any degree). While watching a video on the history of golf, I was amazed to see how the sport was revolutionized during the immediate post-war era. While there were, of course, lots of great players who made the game more easily accessible to more and more people (up to and including Tiger Woods), the biggest change in the game was the availability of cheaper irrigation and ground-repair equipment (namely, tractors). Their near-universal availability following WWII created an explosion in the sport, resulting in an average of one new golf course opening nationwide every single day from 1950-1960. Now, if that isn’t an example of technology trickling down wealth, I don’t know what is.