How Come Death Star 2 Was Ready So Quickly?
When we watch Revenge of the Sith we can see construction under way what must be over 20 years at least before Death Star Classic is finally up and running in ANH.
Discounting the non canon Rogue One and it's stupid idea that they'd just spent twenty odd years building a big round space ship without any idea whether or not they'd get a laser working (!), that means they must have repeated the process in what ? Maybe a year or two for this one...
How could that have even been possible?
What's the explanation for this? Legends and new canon excuses will be acceptable for purposes of discussion...