Only if the mailman walking his route is 100% of the cost and they can carry twice the load every day at no increase in time. Well a lot of the cost is in getting those letters and packages across the country into the mailman's bag, so doing it half as often doesn't save 50%.
Would still save a lot. Also I understand they gave Amazon special, under cost pricing. In Phoenix they carry almost nothing. They park their truck, deliver a few houses and move their truck. Most of what you get in the mail is the weekly flyer which could be delivered weekly, and ther ads.
Email, pay by mail has made them almost obsolete. They don’t even try to change their business model and they let their union run them into the ground.