I'm 100% in agreement. Bonding stones were bad for the game because they made all alternative items pointless, there's a reason why you can't find a current build guide that doesn't include some variant of "get your bonding stones up first because it will provide the biggest benefit" instruction. The gist of the complaints…
Okay, today I was spamming the buttons in frustration, switching between different contribution targets and suddenly it worked vOv I have no idea what led to the change
Rank 3 description contains "Requires: 4 other structures at rank 1" Rank 4 description contains no additional requirements, simply says "Coffer capacity increases. Structures can be upgraded to Rank 2" As I wrote in the OP we definitely have 4 "other structures" (in fact, we have 5), so I'm at a loss