Look, its simple. When someone sells rules those rules have to be clear, working and, for an rpg, must make sense. Doing a half assed job and pileing all the work the designer is supposed to do onto the customer is at best lazy and at worst incompetent, even when you label it with a catchy phrase like "rulings, not rules"
The books bring up the PCs owning properties, give rules for aquiring them and rules for running a business so this rules better work and make sense instead of causing everyone who reads them without rose tinted glasses to shake his head in disbelieve and then ask how this is supposed to even work.
You don't want to see D&D turned into Harn by having something besides dunegon crawling in it? Complain to WotC that they suggest that building a Trade Post is a viable thing for an adventurer to do. But they did and that means good rules would also explain, even in short and simple terms, how to handle a trade post in game instead of the one size fits all business rules which are more likely to cost money than getting you any regardless of the business.
But I guess WotC realized that with rare magic items (didn't stop them to spend 80 pages on them) the only reward they have left is gold and that they need more things to spend money on, so they quickly added construction numbers for trade posts and castles so that the PCs can spend money on something.