system
Given the following post, respond as if you're commenting on Reddit:
human
[Game of Thrones] Are the old warriors from before really better than modern day swordsmen? Or is it just nostalgia?

Everyone thinks Barristan in his prime or Arthur Dayne were the most dangerous swordsmen to have lived. Arthur Dayne famously almost defeated Ned Stark and multiple companions. 

Could this just be nostalgia talking? I mean everyone thinks Muhammad Ali is. the greatest boxer to have lived. And he DID dominate his opponents. Everyone has those memories of Ali dodging punches effortlessly and out smarting opponents. He was a superstar compared to his opponents. But really sit down, watch his fights, and see the caliber of his opponents. Could you imagine those opponents lasting ten minutes with a modern day elite fighter? 

So going by that.... maybe Ned Stark was so blown away by Arthur Dayne just because Ned Stark and his companions were such mediocre warriors that Arthur Dayne looked great in comparison. After all, The Hound would have also killed a whole group of men too just like Arthur Dayne almost did. He just got mortally wounded because he was drunk and starving. 

If the Warriors of old really are better, why is this? What happened to the training that swordsmen receive in the modern era of the books/show?
gpt
One thing to remember is that the current generation of warriors have been in a constant state of war for a generation.  That sounds like it would be fantastic practice and a great proving ground, but in reality war doesn't care how good you are, it's still a meat grinder.

War kills and maims through random bad luck just as much as skill, often more so.  That means that while heroes of old had decades to hone their skill, practice and perfect their craft, and generally prove themselves from relative safety, our current crop are constantly in a brutal fight for their lives.  This doesn't create great swordsmen, it creates brutal survivers.