> why aren't all customer-oriented businesses open 24 hours?
Because that's not the established pattern of work for existing business that are hard to change.
> The equitable future of that type of work is appointment-based.
I think the word "equitable" needs to be replaced with one with some meaning to it. The problem with your suggestion is: should city centres or malls only be populated with shops, cafes and restaurants that are by appointment only? How would that actually change anything regarding what the shop would like to do? They can be open 4 days a week and be appointment-only or walk in. But I imagine a shop that isn't by appointment only will in generally lose compared to a shop that isn't. A restaurant is about the only type of place that can already sustain the premise of appointment-only, and only then likely in a regulatory/property environment that makes it hard to start alternatives.
You're in a mall.
There are 4 shops. 2 require you to make an appointment using an app to pick up food, but the food is fantastic and you get the food when they agree to provide it. The lead time is usually 30 minutes during the busy lunch hour, so you can order before you go to the mall.
The 3rd shop is a McDonalds. They recently got an app and it's great, but ... the underpaid people there are rude, take a long time to prepare your food and half the time they are understaffed because no one wants to work there very long. The food used to be cheap but lately it's not much cheaper than the other places. You've complained about the service before but they tend to have a new manager every month, so you don't believe anyone cares.
The 4th shop has great Dominican food, and they are super friendly. The food is cheap, the service is good, the portions are huge, and it's awesome! But it suddenly closed after you saw ICE agents around one day.
Which is better really?