You're not wrong, although it's more a matter of considering the values of weapons systems when they were up-to-date, not their value today - and no credit for what would have been the costs of storage and eventual disposal that the UAF is 'saving' us.

To be fair, The US does seem to be 'backfilling' the ex-Warsaw nations that have donated their T72s with M1A1s on what appears to be a unit-for-unit basis. Ditto fighter planes with NATO-spec ones. On the other hand, updating those nations to NATO spec was going to have to happen and the old ex-Sov stuff had to be gotten rid of somehow.