In the early 2010s, Electronic Arts made waves by declaring that multiplayer games were the future as it effectively eschewed single-player and narrative-driven games. Around the same time, Sony was all-in on solo player experience with Uncharted 3: Drake's Deception and The Last of Us, among others. But, while EA would eventually change, it appears that Sony is thinking of borrowing a page out of its failed playbook.
According to multiple sources such as VGC, as well as other trusted insiders, a multiplayer Horizon experience is in development.
It's worth noting that Guerilla Games always had a co-op mode planned for the sequel, Horizon Forbidden West. Unfortunately, due to deadlines, it had to put the idea on the back burner. If anything, Guerilla might have just gotten the green light from Sony to release the multiplayer feature as a standalone online game. It might even be a live-service title given Sony's lofty plans for live-service games for the next few years.
At the very least, we can trust Sony to do its franchises right. Ghost of Tsushima: Legends is a good example. Many consider the co-op multiplayer mode for the open-world action RPG game by Sucker Punch Productions to be just as good if not even better than the base game.
However, if we were playing devil's advocate, a multiplayer standalone title that's just like Monster Hunter would be awesome.
In any case, the next few years is going to be huge for the Horizon franchise. A few months ago, Sony confirmed that a live-action adaptation of the Horizon games is in the works. Since then, we've heard rumors of a DLC for Horizon Forbidden West as well as a remake of Horizon Zero Dawn. Fans can also look forward to the PSVR 2 launch title, Horizon Call of the Mountain.
Hopefully, we'll get an update about both announced and unconfirmed Horizon projects in the next few months.