There is a great deal of anticipation for two great sequels from Bethesda and they are Fallout 4 and Elder Scrolls VI. Their respective fan-base is just so huge that any criticism pointed towards them will result in an overwhelming backlash that cannot be stopped.
This is partly why Bethesda is taking things slow in letting out information as they don’t want to be at the losing end of things. Most games today are full of bugs and glitches, which are the things fans wouldn’t want to see in Fallout 4 and Elder Scrolls VI.
To exercise more caution, Bethesda is definitely developing Fallout 4 and Elder Scrolls VI separately. Developing them side-by-side will only result in a lacklustre final product. In detail, the game developer could be outsourcing Fallout 4 to another game developer as they focus on Elder Scrolls VI.
After all, both Fallout 4 and Elder Scrolls VI have little in common, even though they are of the RPG genre. Thinking of them like Bioware’s Mass Effect and Dragon Age is also a mistake.
With that being said, there is a chance for Fallout 4 to come next but developed by another vendor. Then again, it is best to take this with a pinch of salt as it just our view on things.