To better understand this coming conflict I have put together a table of resources and IC to better show the reason each side has to fight.
As you can see EastAsia holds a 29.4% lead in industry and a 62.3% in manpower compared to EuroAmerica. This shows that the new EastAsian Alliance could be a serious threat to EuroAmerica. However EastAsia faces a serious limit to its resource exploitation. While both sides currently have the resources to run their industries right now EuroAmerica can expand its Industry by 738 points on its current resources. On the other hand EastAsia has the ability to expand its industry by only another 119 points.
This would give EuroAmerica a clear advantage in Industry by about 37.0% compared to EastAsia.
Next, many of the countries in the EastAsian Alliance do not actually have the necessary resources to fuel their own economy let alone use resources on defense. As such Finland, with its vast Siberian resources, supplies 38.6% of the metal, and 56.3% of the energy of EastAsia. Without these the EastAsian Nations would be unable to maintain their industry or fight off foreign invaders. By forming this Alliance they are able to secure their resources from a known ally and ensure that it will not be cut off at inconvenient times.