I'm A Banana
Potassium-Rich
I see no reason to assume it doesn't include all assets. For instance, a PC could just as easily find a magic sword, sell it, and use the proceeds to buy some land. It isn't whether they "find" castle deeds so much as how much of the wealth they DO find ends up getting invested in castles and lands.
Well, the reason is that there's no price for them......how much does that castle cost? Does that mean that the farmer's son can have uberequipment, while the noble's daughter has to spend a lot on owning that manor?
*shrug* Easier just to exclude land and holdings from game wealth by level, methinks...since there's no way to compare a castle's value to a magic longsword's, by the book.