Why can’t people just ask for simpler, less custom, prebuilt websites? If you want a custom app then you can always create spaghetti logic, but does a restaurant or small accounting firm really need that?
Restaurants don't even need a dedicated take-out ordering section since delivery apps cover that too.
I rarely see Squarespace or Wix.
They already do.
e.g. our landscaper's website is something like:
bobslandscaping.landscaper.com
It handles the invoices and hosts his basic contact information etc. Sounds like a great business to be in to be the hosting company for this.
Where I live in my part of Europe, most small restaurants, cafes, bakeries etc. only use a Facebook page and their Google maps entry to share their menu, phone number and interact with the customer base. They have no use to spend time and money owning and maintain a website, plus the advantage of even grandmas knowing how to update a Facebook page versus stuff like shopify or squarespace.
And restaurants very commonly have events, either private events closing the place for other guests, or public events with a lot of people wanting to book. In these cases an online platform is even more useful. Then you remove a whole lot of calls.
What makes you think old school restaurants care about that levels of efficiency and optimisations? If they did, they'd all optimize everything till they all become become mcdonalds.
Taking online orders helps them ease a bit of a burden without having any negative effect for the customer experience.
Would you like to have your work interrupted all the time by phone calls?
Today I consult for restaurants and help them get their web presence and the reservation systems they need on their websites. They are very happy for this.
A restaurant usually has their booking calendar open on a display that all the chefs and waiters can check when they walk by. The system doesn't need any human to "apply" reservations or cancellations.
And there is a big difference between being interrupted to take bookings, or checking bookings when you have down-time. But thank you for your hacker sarcasm.
Guests usually call during the day to book tables for the evening or for another evening. In the afternoon between lunch and dinner, there is more time for staff to check bookings. Instead of answering the phone in the middle of morning prep or lunch service.
Then there's events. A venue can have public events with hundreds or thousands of participants. Usually during high season. So now you'd have that additional burden of phone calls, which becomes completely impossible unless you hire additional staff to only take calls. Or you have your own online system which is available 24/7 for customers to make and even pay for their bookings.
Third party reservation systems take anything from 15%-25% to do it for you, which is not really great for the restaurant, compared to buying their own system.
Or if it's an online system for take-away orders or deliveries, these get sent directly to the kitchen ticket printer.
And it's the same for the other small business category: accommodation. The best thing they can do is have their own online booking systems. To increase sales, reduce burden on staff, and reduce expenses to third party providers. And give customers a better experience.