A thought experiment: Imagine that the USPS had, for decades, delivered mail 3 days/week. Would anybody argue that the highest and best use of $10 billion/yr and the labor of 100,000+ Americans would be to extend that to 6 day/wk service? Certainly we have more important needs.

It's easy to argue that since gov't spending seems free right now there's no reason to cut expenses of anything. But opportunity cost is real. I'd argue there are many, many programs/services gov't could fund that would be a better use of resources than 6 day/wk mail delivery.