Shoot you could deliver every other day and they could cut half their costs. Most of what you get is crap. If you need your mail daily get a post office box and pick it up yourself.
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%.
every other day and staggered..
that way 1 carrier could still work full time but could cover 2 routes.