Obviously the role of the game master has broadened since then. Sometimes the game master is simply a referee, someone to make sure all the rules are followed by both the heroes and the monsters. Other times they narrators of the story which the players gets to participate in. Sometimes they are collaborators with the players. And sometimes the role and responsibilities are divided up among everyone.
Originally, I had been thinking about how the role of the game master has evolved but I realized that that wasn't the best word. I think that developed or expanded or broadened it a better term. Because while everyone has their favorite method of running a game, you can't really say one method is better than the other.
In fact, a very good argument can be made that the original idea that the game master was actively trying to kill the players' characters is still alive and well. And, no, I don't mean killer DMs who keep folders of all the characters that they've killed.
Games like Descent are both examples of a game master who is directly competing against the players and games that blur the line between board games and role playing games so much that I easily consider them both.
Back when Descent first came out, a friend of mine was extremely interested in it because he didn't have time to be in a Dungeons & Dragons campaign but he still wanted a D&D experience. At the time, I was in a weekly campaign and I couldn't see the appeal.
Now, since I don't have the time for a weekly game, I can see the appeal. More than that, since I first played Descent, my personal definition of RPGs has broadened with games like The Quiet Year and Microscope. To my mind, a Descent campaign is definitely an RPG.
Ahem. Back to my original point. Over the last few decades, the role of game master has broadened. There's a lot more philosophies out there. However, the old ways have not become obsolete.
What has changed is that we now have more and more games whose rules are tailored for specific kinds of game mastering.
There are some games that are broad enough to cover almost every style of GM. In my years of D&D, I've had GMs out to kill the party, GMs who had the whole game mapped out, GMs who created a sandbox for us to play in, wonderful GMs who actively wanted the players to help build the world and no GM just players just rotating who controlled the monsters.
However, choosing a game it's not just choosing a genre or a setting. Choosing a game it's choosing what kind of story you want to tell and how to tell it.