What's the alternative? If a trashcan of that specification is needed to allow the airplane's mission to begin, then it's grounded until the trashcan is in place.

The alternative is to find a less costly supplier that can meet that specification. Now you've (a) held up the missions and (b) more than likely used up any cost savings in your procurement & supplier evaluation process.

At some point, the intelligent thing to do is shrug, grumble under your breath, and write the check so you can get on with life.