This is interesting but I don't think it fully represents a true "economic" impact of these alliances.
It's only economic in the sense that you can see how much money is directly lost through units/infra lost. Given, that's really as deep as you can go with a stat-tracker website and still be considered reasonable especially with the API limits probably.
Some things to consider would be stuff like:
- Amount of resources spent on attacks and defenses
- (I personally don't think upkeep is a huge difference maker but) upkeep of units for the duration of a months long war
- Did they get a RoI on the expensive higher infra purchases
- A lot of nations have debt to 3rd parties where repayment was interrupted by the war. How will rebuilding and then debt impact their ability to grow in the future?
- How many mines/refineries were decommissioned for the war effort? How many commerce improvements? Basically lost potential income.
And then depending on the picture you want to paint...
- the high-infra losses experienced by some people already had exceeded a RoI. Did they really take a net loss from that infra being destroyed if they made more than it cost to rebuild prior to it being destroyed?
- An inflated resource market might be giving people huge boosts to income that don't reflect on net damages.
etc. There's a lot of factors for an accurate economic picture and depending on the time period you look at... Some people may have experienced a "loss" but not a "net loss".
This is why judging a war's outcome on stats is stupid anyway. I'm much more of a mind to agree that operational control is a signal of victory.