I think that the issue is Todd Howard. He seemingly wants to direct all of the company's big franchise titles, himself. He directed Fallout 3, Skyrim, Fallout 4 and, now, Starfield. I bet that he intends to direct The Elder Scrolls VI, as well, but he can't do that until Starfield is done, so we have to wait another 3-4 years. He'll likely want to direct Fallout 5, himself, as well, so that probably won't be out this decade, as DuncanMacpherson said. I think that he needs to be less selfish and permit others to direct "his" franchises while he's busy. It's not fair to make the fans wait 10-15 years for a sequel just because you insist on directing it, yourself.