In my opinion, Fortnite is already at its peak. Still, I ask myself whether there's still potential upwards? I would be interested in your opinion.
Fortnite itself has potential. However, the target group is not 15-18 but rather 12-14, as is the case with Call of Duty Warzone or similar games, which you can see from the majority of the players. The full potential will probably never be taken out of the game. Personally, I don't play Fortnite, but I think the concept that you don't have any advantages through money is very good. It's free and funded by cosmetic items.
Conclusion: The gameplay itself has a lot of potential. However, Fortnite is not the only Battle Royal Shooter with this feature and graphically it is not an eye-catcher. So you have to like it and not expect too much.
Depending on what the devs change about it, it can go through the roof (more) again, I would say. So there's potential and will probably stay there for a long time.
(By the way, I don't play Fortnite myself, but I like to watch Twitch, provided the streamer is entertaining)