One can think that a predator or a parasite could find interesting the EAB as a food source due to its massive expansion. Nature has probably a plan like that but it takes time to implement and may not be fast enough to save the trees, at least in their main location. Some may survive outside the preferred growth area, or not.
Look at the devastation in the landscape when the elms where targeted by the dutch elm disease. It was a good bunch of years ago, most of the big elms disappeared everywhere, but I still found frequently smaller ones in the wooded areas or in the edges. They can't make it very far and are killed after reaching a certain size, but they are still here. Time will tell.