40 years ago? No cell phones, and no internet to complain about the USPS on. Perhaps it was the same then just that we all hear about the problems now?
There might be something to that. But, as I recollect those days, there was not as much "mail order" stuff done as now. People wanted or needed something, they went to a store to get it. If that wasn't possible/available to them, they might make/have made/grow the item or maybe try mail order. I used to order from a catalog fairly often in the 70's and 80's because they offered me "credit", and low monthly payments (you might can guess what company that is, they are still in business with a commercial on TV). I knew it would take 3 weeks from the time I sent my order in to the time it would be delivered. Whew! Can you imagine the uproar people, used to things like they are now, would pitch if they had to wait like that? haha! But generally, there was more mail in the form of letters and periodicals, and I don't recall my parents complaining about the USPS, and when I was a young adult I don't recall having any issues with them, either.
It does boil down to people though. I have noticed (in abundance) that people now, especially young ones, simply do NOT listen. They grab a word or two of what I say and run with it...often missing the point of what I was trying to say completely. It's aggravating. Maybe if I learned to speak in text it'd help? Sigh.