Canada post dropped Saturday delivery decades ago when it was still called Royal Mail. We somehow managed to survive.
Only delivering Monday through Friday would be fine. I might be in the minority on this board but the USPO does a pretty good job for cheap. Priority mail is way less than sending something ground on UPS or FEDEX and it gets there in the same time or sooner. Mailing a letter is less than 50 cent and will arrive within 2 to 4 days ANYWHERE in the country. Compared to some country’s mail service it’s pretty damn good. I certainly would hate to have to use UPS or FedEx all the time.