Announced Before Oblivion
As noted above, Fallout 3 was under development as something else when Interplay still owned the franchise. However, the Fallout 3 as we know it today began development in 2004. What’s particularly interesting is that it would be announced before The Elder Scrolls 4: Oblivion. Development also didn’t kick into gear until Oblivion released in 2006 but fortunately, it only took Bethesda another two years to release Fallout 3.