We had a family newsagents shop back in the 70s and 80s.
Sundays was our busiest day by far. It wasn't just the odd person coming in for their Sunday newspaper. We were busy for everything really, cigarettes, sweets/chocolates, magazines, groceries, toys, etc. Those were the days when there wasn't anywhere else to buy stuff, no petrol station convenience stores, etc and "normal" shops couldn't open. It was one of the reasons why newsagents were a very popular business to buy, and why they were so expensive to buy! We'd open all day from 6am to 6pm and would probably have sales equal to 3 or 4 "normal" days, so maybe 1/3 of our takings were from one day!
There were a few restrictions on what we could sell. From memory, we couldn't sell greetings cards, but we got around that by putting the cost on the customer's news account, so they effectively took the cards and "bought" them another day when they paid their paper bill at the end of the week! Just like how today shops open early on Sunday for "viewing".
It was bonanza time for us on Easter Sunday (nothing else was open so we could literally sell hundreds of Easter eggs), bonfire night if it fell on a Sunday as people couldn't buy fireworks anywhere else, Mother's day (for flowers and chocolate boxes), etc.
To say even back then that no one wanted to shop on a Sunday is bonkers.