I'd say expanding Fallout setting forward in time is a mistake if they really wanted to keep the IP as "Post-Nuclear". Just right around Fallout 2, it's already questionable how the entire setting counts as "exploring the ethics and civilization of post-apocalyptic world", since Fallout 2 is more like post-post-apocalyptic. Instead of going forward in time, I'd actually prefer to see different parts of the world at roughly the same year the Vault Dweller came out of Vault 13 in search of a water chip, even if only limited to North America. Basically, what happens in different regions of post-nuclear USA, like, I don't know, Salt Lake City? Texas? New Mexico? New York? God-forbid, Washington? Hell, in ideal world, the Las Vegas as depicted in Fallout of Nevada will be THE New Vegas, instead of the New Vegas we see in Fallout: New Vegas.
you could say the same thing about literally ANY IP tho.
To be honest, it's also difficult for literally ANY IP to actually expand and improve in a sequel. A sequel that's 100% faithful to the spirit of its predecessor, while ALSO bring a lot of significant improvement to what was achieved is something that came out once in a blue moon, or even when the stars align with one another. Video games sequels came out more in purpose of building up upon gameplay mechanics and features as the devs and players sees fit, but it's particularly rare for a video game sequel to improve and expand stuff like writings, lore and narrative of its predecessor WHILE 100% faithful to its spirit/experience of the original. Take the Gothic(s) series, and even the Dark Souls series. The first of each IP's games presented the players with overall unique experience, and when the sequels came out they bring a LOT of improvement and expand upon the gameplay mechanics and features of the original. And yet, in terms of other aspect like writings, lore, narratives, level/world designs, etc etc there are a lot of questionable things and design decisions. And then, we have Fallout 1&2. I'm pretty sure we all can agree Fallout 2 bring the best improvement and expansion of Fallout 1's gameplay, but when it comes to the story? The lore? Fallout 2 had a LOT of questionable stuff.
Making it go to space for example could result in a great RPG, specially if it was from the team who made Fallout, but I think it would have been better as a different IP, because the setting is too far away from original one.
Hmm, I'm pretty sure Tim Cain wanted to 'take' Fallout to space, as in making a space game that's based in Fallout setting of history (the nukes hit in 2077, the Master is defeated in 2160s, then after a lot of rebuilding, mankind gets to live in space in maybe 2500s or something). Does that counts as different IP?