As an experienced author of textbooks, 9 of them over the years, I can attest that productions like that:-
- are not simple, easy or cheap to create
- take a long time. 12 months was about the fastest I ever achieved and in that case I was one of several authors (but was also the overall editor). As I sometimes discovered, editing the work of others can be as time consuming as writing their work all over again.
- once written are not easy to change. This applies to PDF as well as web and paper based - and I have experience in writing docs in all those formats
With technical documentation (such as a software manual) one of the major issues is keeping it up to date. Each time a new version, service pack, even a hot fix, is released changes have to be made to the manual.
One way around that issue is to only start writing the manual after all the changes have been made and the "final product" (does that actually exist anymore?) is released. It would be like releasing the manual for T:ANE after its support end date had been reached. The time delay would be unacceptable to most users.
Another often proposed solution is to start the manual writing at the same time the project is started so both can be released together. But, as any developer will tell you, the final product can be totally different from its starting plans or first few prototypes. Last minute (just before the release deadline) changes can cause havoc for the writers. So there will be a lot of wasted time and effort on the part of the documentation writers.
While we are on this nostalgia trip - remember the good old days when software came on floppy disks with volumes of printed manuals? My first copy of MS Word (I forget which version) came on multiple 3.5inch floppy disks (remember them?) and a box of manuals weighing several kilograms. That alone would explain the high cost, even back then, of the software.
I just had a look at my main commercial (purchased) software applications. Not one of them has a manual, PDF or web based, that comes anywhere near the standard or detail shown in that original Trainz manual. I take my hat off to the writers of that manual but we will never see the likes of that again (not unless the users are prepared to pay much more to cover the time and effort that went into its production).
My thoughts.