It’s been pointed out five day a week delivery removes the need for a second mail carrier required to deliver mail six days a week.
As
@SC Maintenance also mentioned
The savings eliminating that extra person is massive. We’re not only talking about weekly salary, we’re talking about benefits, such as health and retirement. We are also talking about the massive reduction in overtime.
Contrary to another post from you, I don’t think you thought about the amount of overtime carriers work on certain routes when a replacement can’t be found for their day off.
The volume of mail in a postal carriers workday is much less than it used to be yet that carrier still has to bring that mail six days a week to each address.
The volume of mail delivered by the typical mail carrier today is 46% less than 30 years ago.
Yet that male carrier still has to go to each and every address six days a week
https://www.uspsoig.gov/reports/white-papers/analysis-historical-mail-volume-trends
It is completely insane to continue six days a week delivery and it should’ve been cut out a long time ago