KelllyG, our experience with injections (TreeAzin) in southern Ontario is that is has slightly flattened out mortality curve, but is not a cure. Generally by the time you have a visual confirmation that EAB is present, it has been in the area for a number of years. At that point injection will slow down the growth of individuals in the tree, but not eliminate it completely. Injections (or other pesticide applications) are not a magic wand on this one.
EAB is unlike anything we have seen before, the biomechanics of the decline make the trees more dangerous more quickly. We are seeing tree after tree with no signs visible from the ground failing, in some cases dramatically; and when the crews are doing removals trees that seem "fine" are brittle and doing unexpected things. With the exception of a few "heritage" trees that we will save as long as possible (continue to inject), we will be removing all ash in our municipality.
I know the provincial seed bank in Angus (Ontario) has been for a while actively building a cache of seed stock covering a range of seed zones, species, and genetics; hopefully if/when we hit balance with this one, there will be a bank to draw from.