Second Death Star Construction Time

[Darth Cronos the Proud]

I just got done watching RotJ, and a thought occured to me. At the end of RotS, we see Vader, the Emperor, and Tarkin looking out the window of a Star Destroyer's bridge at the frame of the first Death Star. Fast forward to ANH (19 years later) and the first Death Star is finally completed and then destroyed. Fast forward again to RotJ. The second Death Star (which I believe is described as being larger than the first in the novelization and other official literature) is almost three quarters complete, as well as having its superlaser operational.

This is what bugs me: The first Death Star took almost 20 years to complete, during a timespan when the Rebellion was not as organized as it was during Episodes 4, 5, and 6. Even if we say that the Emperor ordered construction to begin on the second Death Star immediately after the first one's destruction (and it couldn't have been any earlier because in the official literature it describes how the Emperor tortured Bevel Lemlisk for his failure to overlook such a design flaw, then ordered him to redesign the Death Star without it), it still would only have taken four years (less than a quarter the time it took to build the first Death Star) to get a larger version of the first Death Star three quarters complete at a time when the Rebellion was highly organized and required massive Imperial resources to combat. How is this possible?

[Vympel]

This issue has been raised before in previous threads, newcomer. IMO, that the original Death Star was the first of its kind, and had to be produced in an environment where the Imperial Senate had not been disbanded, serves to explain the discrepancy. The Empire having problems with building it quickly isn't unreasonable and is actually quite realistic when you consider modern military procurement problems.

George Lucas' commentary on the RotS DVD seems to agree with this point of view (for those who think George Lucas doesn't really "get" the scale of the galaxy he created, his comments re how long the first Death Star took to build should set their mind at ease that he is quite aware of what a feat the construction of the Death Stars were- his "even for the Empire" comment is well enough illustration of that).