Back when I first started playing RPGs, a little over 25(!) years ago, there was a certain, established order. RPGs were a three-way dance between the players, the GM, and the game.
The players played the game. They had few responsibilities aside from showing up and having a good time.
The GM, oftentimes the sole owner of the gamebook, organized the get-together, learned the rules, studied (or wrote) the adventure, and interpreted the various actions and dice-rolls to put together the world of the game, and to direct the story of the adventure. The GM, contrasted to the players, had a lot of responsibility, but the trade-off was more control over the game. The GM's fun was derived from the players' fun...in other words, if the players were having fun, the GM was having fun.
The game was, naturally, the backbone of the entire get-together. It clearly communicated the rules, oftentimes provided the actual adventure, and created the entire world the players role-played in. The game has the most responsibility, as it dictates literally everything the players and GM can and can't do, not to mention it came to the layout and writing of the game to communicate the rules, and the artwork and stylistic touchers often to inspire or set the stage of the game. In return, though, the game designers are facilitating play across the world with groups of gamers, and even making a little money to boot.
That was how RPGs used to be, and (cue crotchety old coot voice) that's the way we liked it, dangnabit!
Many modern RPGs have altered that order. There's a new balance between the three "factions" in a role-playing game. The players in today's games oftentimes share the burden of telling the story and understanding the rules. Some of today's games, like Fate Core, practically demand the players understand the game as well as the GM in order for the adventure to be run optimally. Today's GM has fewer responsibilites in the rules front, but oftentimes because of the added responsibility to the players, the GM becomes an "ambassador" for the game, helping teach the rules to players so that they understand their part in the game and can contribute properly. Today's games are often written as highly-collaborative affairs, requiring an even give-and-take between players and GM to run optimally. Furthermore, many of the details of modern RPGs have been lessened, removed, or delegated to sourcebooks with the understanding that those missing details will instead be filled in by the players and GM.
Is this a bad thing? Absolutely not. The players have more creative control, the GMs have less responsibility, and the games don't have to be so meticulously written.
Is it a completely good thing, though? Not necessarily. I am an old-school, fire-and-brimstone GM. I can hang and bang with the new games as well as anyone out there, but if I'm being honest, I am at my best (and having the most fun), when I enter a room and I'm the only person who completely knows how to play the game. I am most comfortable in a game where the players can't spend a My Turn token and take over the story. I am at my best as a GM when facilitating the story falls on me and me alone. It's what I'm used to. It's what I've done for over two decades.
I bring all of this up because I've been thinking a lot about Fate Core recently. I really, really love Fate. Its flexibility and versatility is unmatched in the industry. However, there is one problem I have with the game that I cannot avoid: a good, "legit" game of Fate requires players to know the game as well as I do. I've heard some people call this "metagame," and I would agree. I think about the person who clicks "yes" on my Meetup gathering, having never played a role-playing game before, and think about how it's going to be on me to tell that person how to play, and then expect that person to pull their weight at creating the story at the table. This, as opposed to an older game, like, say, Call of Cthulhu, where the die-hard veteran and the complete newb are both essentially on the same page: the page I tell them they're on!
Not to just pick on Fate Core, but there are many other new-school RPGs that are the same way. Take Dungeon World, for example. I absolutely love Dungeon World. But to really get into DW, the players at the table have to "get it." When the Bard uses Bardic Knowledge and I ask him or her how they know that, they can't just give me the Deer in the Headlights look; the Bard, or someone else at the table, has got to come up with something. If it falls back to me, then much of the magic of DW is lost, and we might as well dust off our old red box edition of D&D, instead.
I guess where I'm going with all of this is here: when one looks at all the hot new RPGs, it's tempting to say that older styles of play are obsolete and the future is "collaborative storytelling" style games. If that is true...and I believe it's not, just look at the ton of OSR games out there...then we are ignoring a very real segment of the RPG community: all the players out there who want to explore a world, not create one.