The biggest problem is where to get more Soviet tanks, or fighter jets as the case may be. The WarPac stockpiles are depleted. The US has drawn on them many times for things like re-arming Iraq, or Afghanistan. There's some more Soviet gear in Finland, and some can be scrounged all over the third world, but some sort of transition is inevitable. I think there's a serious question western decision makers have to ask themselves - what kind of resources are they willing to commit? It appears some Su-25s and some MiG-29s from Eastern Europe have been handed over to Ukraine, by parties unknown and without much publicity. In some areas, like APCs, western equipment is relatively easy to adopt. In some areas, like machineguns, it practically adopts itself (Ukraine had a machinegun shortage pre-war, those Maxim guns weren't pulled out of storage because they were doing well). In some areas, like artillery and MBTs, it's very difficult and expensive. The US really broke the ice in the artillery department by providing over 100 155mm guns, and appropriate quantities of ammo. It made it easier for other partners to piggy-back off of this. Will the US take a similar role in MBT and fighter jet programs? It will be at a much greater financial cost, especially the fighter jet ones.