With ever increasing online purchases leading to more mail, (especially packages) , a shorter delivery schedule for the Post Office would probably just make more business for UPS, Fedex, Etc.
Also, no matter how the post office cuts costs or raises more money, (like postage increases), they never get ahead. I would assume customers would just end up with less service and a Post Office that is still broke and in the red. After all, less service and higher postage costs is what the Post Office has been delivering for years.
