Bethesda might have been the one to revive Fallout and give it a new facelift, but it was Obsidian Entertainment that made the better game. After releasing Fallout 3 in 2008, Obsidian got a chance to work on Fallout: New Vegas, which received much critical acclaim and commercial success in 2010. To date, many consider New Vegas as the best Fallout game and possibly one of the best spin-offs of all time. However, Obsidian never got a chance to release a sequel - until now.
There are ongoing reports that Microsoft is considering giving Obsidian a shot at a long-overdue New Vegas sequel. In particular, Jeff Grub, as reported by VGC, mentioned that the words "Obsidian" and "New Vegas 2" are floating around right now. Unfortunately, Grubb also clarified that there are no plans in motion yet, but that Microsoft is very interested in making it happen. Considering that the tech giant is now footing the bill, we wouldn't be surprised if this rumor ends up coming to fruition.
The only problem here is that Obsidian probably won't be able to work on New Vegas 2 until at least 2023. The Outer Worlds developers are still working on Avowed right now, which is reportedly scheduled for a 2023 release. Meanwhile, a sequel to The Outer Worlds is still on Obsidian's docket. Not to mention, Bethesda confirmed that it had already started working on Fallout 5. Naturally, the fifth mainline Fallout game would take precedence over a sequel to a spin-off.