Hopefully this gives you some insight! Also this is from a programmers perspective so feel free to correct me
@Snow Crystal !
I don't think there's anything to correct here, as I think we feel quite similarly about most of these things, but I can add some things from a CD perspective.
The team steadily grows during development. If a game has spent 3-5 years in development dosn't mean it would have a full complement of content designers churning out content from day one.
This is very true. The later you are in development (before release), the more people you have on the project. So you'll see a larger upswing of things being added later in development, as all the puzzle pieces come together. This is particularly true of content, who often struggle to do very much (of super visible content, a la events, missions, etc) when most of the systems are missing, design hasn't been finalized, etc.
Game mechanics takes programming time to finish. Even if you plan out the content it's gonna take awhile until you can implement, test and tweak them.
This can be an absolute struggle when things actually come together. More than once I've spent just as much time going back to content, fixing them when the systems have actually been put into place, to make them work with the final version of systems. Too often I have had people ask me how things can take as much time as they do, and the answer is "iterations". The example I always come back to, is the deity system we ended up with in Imperator, that had (I believe?) 5-6 different iterations for patch 1.4. Every single time that happened, I manually went through our whole list of deities and had to tweak/add/remove a small piece of Script, to make it work with the new system.
Mechanics are iterated on during development. Sometimes a whole mechanic might get scrapped and so may any content made for it. Has happened atleast once on my project.
Jupp, I've had to cut events/content because of changes made previously. Of course, we try to make these cuts early, but it's not always it works out as we would have liked. Also, there are times when content just makes less sense, and we cut it for that reason, even though we could have tweaked it to still work. More content isn't always better, if the content ends up being sub-par.
Porting old content is atleast as time consuming as writing new content. The engine/script system evolves between franchise cycles. Features gets added or removed. Content has to align with new design & art vision. If CK3 released with CK2 content wouldn't it be strange if no events ever referenced Lifestyle choices?
Also, look back at what was said earlier about tweaking content even in a single patch cycle. Now imagine that, but with thousands of events. It's honestly a pointless endeavor to bring back content from older games wholesale, when you could focus your efforts on writing new content instead. And my personal opinion is also that events we write these days, for the most part, are better than events that was written in our earlier games. I sure as hell wouldn't want anyone to start porting over dumb things I did in CK2 to CK3, as an example.
Provinces, resources, flags, pops, units, national ideas, lifestyle and tech trees, countries, characters, etc has to be setup and continously rebalanced for a whole world, sometimes from scratch
This is incredibly time consuming. The amount of time and effort that goes into actually crafting these worlds are massive, and they are massive for every single game we make. It means that the few CDs who are on a project, often spend the first half a year/year just making the map and the base stuff (unless they are an actual robot, like Arheo who did it in an incredibly short amount of time).
Time spent planning & laying the groundwork/guidelines for how years of future DLC is going to be written
The planning phase is substantial on every project I've been, and it is a bit of an on-going thing. The simple fact is that if we had continued to develop a game until we were out of ideas for a release, we'd never be done with it. So knowing that a scope has to be limited, you often come up with a large amount of ideas for what can be done later down the line. E.g we knew about the naval changes we'd make for 1.1 a long time before we released the game, even though that meant the naval game at release would be worse off.