A "historically significant game"? Wow. I like the second explanation better. 
Why has chess survived?
Sort:
same board as checkers.
It's a game of intellect, it's a game of tradition. That's all there is to it. Being one of the most historically significant games, one should expect it's survival. Although not the most popular of games, it will never die. Perhaps modified on rare occasion.
Maybe it's just fun to play. I like the first explanation better, but I have a feeling most people will go with the latter.