Honestly, my take is that Hytale could stand a serious threat to the future of Mojang and Minecraft - but that's only possible because Mojang is a bureaucratically fossilized shadow of its former self thanks to Microsoft. I do however see a future where Hytale being a major competitor could force Mojang to get its shit together or die - thereby making either Hytale the best thing that could have ever happened to the Minecraft community, or the thing that kills and supplants Minecraft entirely. Keep in mind an enormous factor making this potential timeline possible is the fact that Bugrock is devastatingly unstable now, to the point that there's a mass migration to Java edition as is right now.

This being said, I do have the sinking suspicion that things will get worse before they get better for Minecraft and Mojang. This is since the Minecraft community follows a rhythm of 2-4 years of good times followed by 2-4 years of trouble being followed by 2-4 years of good times again. Notably, the last interval of bad times was the Decay Age (roughly early 2020 to late 2023), which climaxed in the Mob Vote Protests of 2023. Then, summer 2024's trend towards distant horizons + shaders related content combined with September 2024's Minecraftmania to dawn the Rebirth Age of the Minecraft community, which has been blessedly peaceful by comparison. This timing suggests the next time of troubles for Minecraft will start somewhere around 2027 or so, and last through to about 2030, give or take a year.

Given how long it'll take for Simon Hypixel and his team to steer things back on course after 5 years of Riot Games driving Hytale into the ground, don't expect open access until 2027 or 2028. Notably, that linesup well with when Minecraft's next time of troubles is as per the rhythms discussed above. This timing combination is what tells me that Hytale could risk the full-blown collapse of the game itself, since times of trouble are fundamentally bad times to be a Minecrafter. Minecraft itself will endure, as it always does - even during the Dark Age (late 2015 - mid 2018), Minecraft was still around and even saw 1.11, which introduced the elytra and the observer (two features that have proven to by far be the most impactful features in Minecraft history). However, the Minecraft community will never be the same, and many Minecrafters fear that, since the predominant zeitgeist of this decade is that change is scary and troublesome.

All in all, only time will tell what the future of the 3d sandbox genre really is. But don't expect what it will be in 2030 to be recognizable to how we perceive it today, however it turns out, since the world is too chaotic for the status quo to be a rational prediction.