Using Morrowind as the base I'll give an example.
4 years after Morrowind = Oblivion had double(if not more) the surface area
5 years after Oblivion = Skyrim, while having close to the same square mileage as Oblivion, has close to double the Surface Area because of the excess of mountains & hills.
Give them a few years & Tamriel will be a reality. Maybe in 30-40 years we'll be given the entire Elder Scrolls world as our playground. Did you know that supposedly in about 20 years Computers will work as fast as the human mind. Anyone here ever hear of a Blue Box or a Quantum Computer? They are right around the corner.
That's totally baseless. Adding a few more mountains would not DOUBLE the surface area, and they still only have to populate the same area, you don't have twice as many buildings or trees because the incline is doubled. And Morrowind was 11 square miles, Oblivion was 16, so again, not doubled or even close. Also, Morrowind had more content in it's world than Oblivion. And like I said, but you people seem to be too stupid to understand, it's not a matter of technology, it's a matter of simple human effort. Daggerfall was thousands of times the size of Oblivion, so how does that fit into your idea? Making a large world is easy, anyone can do it, they can create entire galaxies (literally) using today's technology. The challenge is filling it with meaningful content.