I imagine the reason is "server architecture." However as something both useful now and 2.0:

The recipe section on the lodestone does a decent dynamic search.
The Mythril Eye is supposed to be a trade paper. It appears on lodestone for flavor.
The recent transaction stuff seems like it could be pulled just like player achievements are.

Add the Mythril eye as a way to search server and wards for sell prices. It obviously has a decent delay but whatchu gonna do?
There you go a lore appropriate way to search on the official site keeping lag out of game.