Comment by p_l

Foreign Military Sales from USA all go under a very ugly kind of contract where you could argue you're not sure of delivery until after the gear was decommissioned and turned into razor blades. You can't (officially) negotiate it, you can't demand accountability on actual deliveries, the real delivery time is "whenever we get to it", and so on.

It's just that until recently USA at least pretended to care to not use those provisions too much.