You hit the mark dead on. Most of us would pay a few bucks more for a really worth while manual. Some of the older sims Fighting Steel. 688i. Fleet command, and Fast Attack had detailed manuals that made the learning easy.
There are some Falcon 4.0 Allied Force is darn detailed I have never mastered any thing but crashing, but much of that is probably due to my lack of interest in Flight Sims, I am not much on first person shooters either.
But like you I will pay for a good manual. Running one off from the disk-Falcon 4.0- cost as much if not more as a already printed manual.
I don't know maybe the added cost of a manual would dissuade some from buying.
They may simply rely on SUBSIM and players like you to figure out and help others. I know I do all I can for other players, my present expertise is with the older sims. NOT AN EXPERT on DW, especially the aircraft and the FFG. About all I have learned is from this site and the forums on the SH4 site.
Thanks and you have a good day,
Ron