The long-standing problem with every game ever made is a little thing called diminishing returns. This issue is especially prevalent in shooters because the players race through the exact same gameplay loop ad nauseam. This is why shooters tend to launch hot and quickly burn through their player base which, in the modern game saturated climate, is more than happy to hop onto the next latest greatest thing.
Now, because I write to snarky gamer types like myself, I want to note that there are outliers. There are games that people love for the repetition and lack of change. They find that loop a safe space for them to get into a zen dripped flow state as they play their cares away. I'm not talking about the two percenters, I'm talking about the broad majorities here because, like it or not, games live and die on the wallets of the unwashed masses.
Fortnite may be the single finest example of a shooter integrating every angle it can to prevent players from leaving. The result is quite refreshing. It is a game that is never stagnant because the developer doesn't just make changes, they add and remove entire game modes ever few weeks to months. This serves two-fold, it keeps the game fresher longer and it leaves players wanting more rather than allowing them to play until burn out and move on.
The danger of this technique and the reason other games haven't been able to pull it off, is gamers tend to be a fickle lot. One wrong move, like announcing a phone game to your very PC customer base, can send us into a firestorm of rage. Prior games would make adjustments, even tiny ones, and effectively kill their game with a single download of content. MMORPGers are especially familiar with this phenomena. (Pours libations for DAOC, UO, SWG)
The reason Fortnite has been able to pull this off is two-fold. One, they have done it from very early on in their process. While there is still a vocal minority of players that long for where this game was heading before it went mainstream, the majority of its base came in after the developers had implemented the rotational content model. Their base didn't get a chance to lock into what the game was because to them, the game is constantly rotating, that is their normal.
The other reason is timing, specifically technological timing. In the dark ages, a content addition took a large volume of resources; time, money, broken marriages etc. It wasn't easy to patch in and once it did, it was harder yet to undo. The lag between a new patch and a repair was long enough to drive players away in the interim. Thanks to modern advances game development is moving faster than ever. The modern tools allow developers more creative freedom to try new things, retain what sticks and rework what flopped.
The end result is a shooter that never feels stagnant because its constantly giving you new things to see, and try. (And buy.) The reason this approach is column-worthy is simple, the gaming industry is incredibly trendy. Despite the fact that they rarely reach the potential of the games they are borrowing from, every time a game breaks out, clones are sure to follow. The positive isn't the cloning phase, its what comes after. Would a game like Fornite have building and full destruction if not for a game like Minecraft? You see, it's not the blatant clone that excited me. It's the successful bits and pieces that carry on past the clones and become industry standards, evolving all of gaming into a higher form. (Until its inevitable final form, the Matrix.)
That's the long way of saying while Fornite remains a contentious topic, the things it does well are going to be cloned, naturally selected and integrated, taking shooters and maybe even some MMORPGs to better places as a result. Gaming is watching evolution in real time. You might not like a game like Fornite, but the masses selecting it are assuring its DNA, specifically the most successful parts, will get passed on through developmental generations. For better, or for worse.