Clinging to our ideals above our else will cause the civ's demise; refusal to adapt to changing situations will result in us becoming increasingly irrelevant until we suffer a similar fate to the Spirit Talkers in PoC.
Temp econ losses don't affect that much, since we're not going to be doing infrastructural projects or whatever during a war.
I have not suggested we should "Clinging to our ideals above our else", just that we should consider what suits our civilisation.
"refusal to adapt to changing situations will result in us becoming increasingly irrelevant" so we should adapt and chose the new value Sacred War. Yes, we won against the Merntir with numbers but that will be less useful against nomads. The new (and foreseeable future) situation is one were elite units are needed to support our regular forces
But we'll somehow be able to afford Warriors that are even more expensive than normal because....
Obviously most of our warriors will be the (cheap) regular ones.
Cateyes are also more costly than regular hunters, should we get rid of them?
Heroes are very costly and extremely rare, do you think we should have no more Heroes?
So quick people are, to give up all power to a bunch of shitty elites who are going to fuck us over in the long term.
Sacred War is what caused the collapse of the Spirit Talkers, it's not a good solution.
The religious value Born Equal means we won't be giving "up all power to a bunch of shitty elites". We dump that value, or pick up an elite one, then we will have problems.
Sacred War is not a stratification value (born equal therefore we recruit from all), and the goddess will intervene if any of our people attempt it.
We are not an AI civ, that is a false comparison. Sacred War is not what caused the collapse of the Spirit Talkers, depending on tribute for food is. (sacred war caused them major problems, but is not what caused their end)
In PoC we had Sacred War and still ended the war against the Dead Priests, at the cost of stability but we made that choice.