Our family had a "traditional" corner newsagents shop for 20 years from around 1975 to 1995. We opened 6am to 6pm Monday to Saturday and 6am to 1pm on Sundays, with wednesday half day closing from 1 to 4 (had to reopen for evening papers).
Many times we tried longer opening hours, but the trade never justified it. Even when we got the National Lottery and had to open later on Saturday evenings for people to buy last minute tickets, it was ridiculously quiet. I remember one Summer, we decided to open all day on the Sunday, and we tried it out for about 3 months - we'd be lucky to see more than a couple of customers each afternoon. We were also there later on Tuesday and Thursday evenings to mark up the local newspapers for delivery Wed and Fri morning (there were hundreds to mark up as nearly everyone got a local paper in those days) - we were there, so we'd be open, but, again, no one came near.
The one and only time it was really worth opening, was a one-off hot air balloon rally in a field opposite - it was a hot & sunny day, and we literally sold out of soft drinks, ice creams, etc - that was simply from people attending the rally, not locals.
We have a small pie/sandwich shop in our village. New owners took it over last Summer. They tried all sorts at first, longer opening hours, broader product range, lots of local advertising including heavy presence on local Facebook groups, leaflet drops, etc. We have a big fireworks display so they opened late afternoon and early evening on Bonfire night in the hope of getting passing trade as hundreds of people walk to/from the field past the shop. They won't be bothering again as it cost them more than they made as barely anyone went in (they should have known really as the village chip shop closes early on bonfire nights due to lack of trade, despite hundreds of people in the village!). The pie/sandwich shop has now gone back to closing early and back to simple pies/bacon buns etc as that's where the money is - they couldn't justify paying staff to work afternoons when there was no trade!
I have no doubt at all that "some" small shops are run badly and many will be "vanity" projects, especially hobby/dress type shops run by someone who just wants something to do for pin money rather than trying to make a living! But I think most are actually run professionally and the owners take proper business decisions as to when they open and what they sell based on experience. You can't stay open extra hours for a handful of customers. Yes, there's the chicken and egg situation, but how many months/years do you run extra hours at a loss until critical mass means it's actually worth opening?