What code they were learning? Like from RCT2 code? Is there an article about the development somewhere actually?
This "learning" was nothing else but normal development and they worked on the game and it´s engine.
Im sorry, are you trying to downplay development time and effort?
If there is anything I've learned from years of working in development, its that almost nothing is what you think it is. Most of the times its harder then you can imagine. Sometimes on a rare occasion its simpler. But your always learning something. Always in the need of improving something. Always being humbled.
And research is very much a part of the development process. A time consuming one.