That's the prevailing conventional wisdom, but it doesn't take the facts into account.
Saturday is not a "slow" mail day. The volume of mail delivered is roughly the same as any weekday.
Monday is a very heavy mail day. All the letters, magazines, and junk continue to flow through the system on Sunday even though there's no delivery. Mondays are hard.
Now, as the plan goes, we will add Saturday's mail to Sunday's and Monday's and -- just like the underpants gnomes planned -- profit will result. And don't even mention three-day weekends.
The mail volume on Mondays will now be crushing. Either more workers will need to be brought in to sort and deliver it [eliminating the savings] or it will simply stack up in the P.O. and trickle out during the week as staffing permits.
Also, there is a small army of substitute carriers who work Saturdays and the regular carrier's vacation and sick days. Eliminating Saturday deliveries will cause most of them to seek other work. It's their only guaranteed work day.
This will cause tremendous problems in coverage down the road.
It's such a crazy proposal that I suspect it is just a negotiating ploy to get Congress to get off its fat ass and end the stupid health care pre-payments that are causing 90% of the losses.