The only games remotely like the Elder Scrolls games are Fallout 3 and New Vegas, which are both Bethesda games. They even run on the Elder Scrolls engine, Gamebryo. Also, Oblivion and Skyrim both had huge advertising campaigns. The typical RPG these days is actually more in the Diablo style than the Elder Scrolls style, since you can make a hack-n-slash with a select few predefined character types with a fairly small team.
Making a similar game would require an enormous capital investment, which is why no one else will do it. Skyrim was an $85 million game. The only companies big enough to even attempt that sort of thing are Activision and EA. Activision’s got WoW and Diablo, so they have no need to take the kind of financial risk required to compete with Bethesda directly. EA’s Dragon Age and Mass Effect games don’t sell as well as the Elder Scrolls games, but they also cost much less money to make (EA is trying to compete with Call of Duty now and failing miserably). Sure, ES games are incoherent, structurally broken, buggy messes, but they are also the only open-world RPGs on the market. If you want to play an RPG where you wander around in an enormous world and do whatever you want, Bethesda’s the only game in town.
Skyrim sells tens of millions. Many companies want a piece of that pie. Including the makers of Dark Souls.