Like any artform fantasy is susceptible to change. Think of 60s rock-and-roll and compare it to modern rock, 90s cartoons compared to cartoons today. Just like how music is changing due to technology, fantasy is changing due to a flux of information on the internet. The re-discovery of medieval combat treatises is putting a heavy responsibility on the shoulders of everyone who works with medieval themes, especially writers. But as things change the more they stay the same.