When I was in Berlin I was surprised grocery stores were open so short on Sunday. However, regardless of religion, it has a side effect that horeca workers (which -I kid you not-
is tough labour) can have a guaranteed half day off on that one day. That's a disadvantage of the 24/7 economy: workers who do certain tough labour jobs who are replaceable (a relatively non-unique skillset) have less rights.
> Who goes and buys a TV for example at 11am on a weekday?
What happens at say grocery stores is they have less workers at the non-peak times, and workers do different tasks at different times of the day. Instead of being clerk, they for example replenish from the warehouse or throw away items which are past their due date. You'd have only 1 or even 0 clerks, but there's also hardly any customers. Meantime, all these workers can still be productive elsewhere.
In your specific example I can imagine a clerk doing inventory or online orders during downtime. Though it depends also on the size of the store.
As for who buys that, grandpa & grandma, the guy who took a day off to buy a new TV (tho nowadays one can buy TVs online just as well, and why not [1]), or the mom who's a housewife or has a part-time job (latter being very common for females here in The Netherlands).
[1] I'm getting on a tangent here geez but if I'd buy the TV online here in the Netherlands I'd also have 2 weeks to send it back for whatever reason other than warranty. I don't have that right if I buy it in brick & mortar store other than warranty. A good reason to shop online indeed!