I actually used to open around 5am and I was the only person open at that time near a major highway so work crews would line up out the door for focaccia, donuts, and muffins until after 8

Then it would be dead for 4 hours

Then line again

Then dead for 6 hours

Then closed.

The major issue is staying open has to justify the cost of employees and while bread is particularly good for turnover rate, food in general has a very low margin and bread has low shelf life. Also, the facilities ideally should be cleaned between uses so you have to schedule downtime even while staying open.

But yes an urban environment should have more night options.