Why are you even in this conversation. All you're doing is being a downer.
Obviously, you haven't done the calculations either so you don't know what you're talking about. My guess turned out to be pretty accurate based on the calculations above. You can't buy affection items with kobans. You can only restock the market. You're right you can pay kobans for the upgrades and that would alleviate the issue substantially. The values make no sense. Red battler costs 200 kobans for 5* and Rabbi costs 550 for 3*. $3.96 million and 396k respectively. So maybe they are banking on people getting frustrated with the grind and spending kobans. Would work better if upgrading the girls actually meant something for pvp.