I think it's partly because this is what was started and caught on. There are also folk life festivals with traditional art forms from before mass production,

I think it's partly because this is what was started and caught on. There are also folk life festivals with traditional art forms from before mass production, frontier festivals, colonial festivals, Civil War reenactments, Revolutionary War reenactments, the Vintage Computer Festivals, conventions for antique radio and TV equipment, and all sorts of periods people commemorate. This is the one that has been around a few decades, caught on in a big way, and spread nationwide. There are also pumpkin festivals, apple festivals, corn festivals, other harvest festivals, May Day festivals, county fairs, state fairs, and more despite most of the things involved in all of these are anachronistic for most of the population. Very few people actually raise prize cattle, sheep, and pigs. Very few farm crops. We still celebrate these as if we’re an agrarian society though.