I happen to be a three-minute walk away from the post office on rue Principale. So I see everyone go by, and I also see the post office. I have noticed that some shopkeepers don't go everyday. Increasingly, especially in remote regions, people have learned to use the Internet to reduce costs as well. We still rely on letter carriers a lot, because there is no way around that. Some letter carriers still drive to serve the rural routes.
I had not expected the thing about the people waiting for cheques, either. I think an adjustment can be made, since we know that some cheques come in on a set date.
In terms of mailing documents, I personally call Purolator if I have to send a document quickly. I had to send something to Service Canada recently, so I called Purolator and it was delivered the next day. Purolator is an option and is a Canada Post service. So one service can make up for the other.