Why do you assume that those tasks won't be automated? To some extent they already are in some places (kiosk ordering at some fast food places, cleaning devices à la Roomba).
Roomba's are really slow. There's no robot that can quickly find and clean a spill while keep people around the area safe. That kind of progress hasn't been made with robots and AI.
You can have something like a system where the restaurant is a big box that cleaned automatically, yes, but then it also becomes unpleasant. Kiosk ordering might work but then cashier is also the "public face" of restaurant.
It all comes down to "why do people go to restaurants instead of microwaving Trader Joe's stuff", right?
That's true today, but don't you think artificial intelligence will change that?
AI has made a lot of strides doing what it's good at and basically stagnated outside that realm (it's been forty years since the first seemingly intelligent system appeared and none of these systems has become good at dealing with an uncontrolled environment). AI hasn't gotten noticeably better at dealing with complex and confusing environments.
[1] http://www.marketresearchworld.net/index.php?option=com_cont...
The point isn't that automated food service is impossible. It's certainly possible. Indeed, it's been around for a long time [1]. The point is that it isn't necessarily a better investment than human-run food service and thus human-run food service may stay around a long time.
http://www.popsci.com/gadgets/article/2010-04/students-inven...
Notice that it is created to manufacture Chinese food. A change in taste to Korean might obsolete it.
Prototypes can do lots of things. They tend to have durability and reliability problems.
Plus, many chefs I know also have durability and reliabilty problems.
Try baked Italian dishes. Clearly there's a limit to the thing's flexibility. Not all Chinese dishes was conventional wok cooking for example.
Also, most humans aren't reliable but generally, you "rent" them rather than buying them - your cook get truly unreliable, you can find another cook. You would almost certainly have to buy a specialize Chinese food (or Wok-cooking) machine and so you'd be providing not just "health insurance" but "health care" for it if it broke down.
The only way to have a completely automated restaurant is have a big box that spits out meals. The alternative is no automation or a lot of little boxes that are used for pieces.
The thing is that a restaurant would still needs counter-help and clean-up help so further. Let's assume the box reduces the cost of prep-labor by 50%. That reduces the labor past of your costs by 25% and your total costs by 12.5% assuming labor is 50% of costs. So it's a good savings but not an astronomical savings. But the counter-weight you have sell people on buying the food that comes out of the box. A few places compete on price alone but that's hard. Just consider that restaurants are already competing with microwave dinners in the frozen section that quite possibly are already spat out of a better, cleverer box at a central factory. It would seem restaurants compete on ambiance and human relations and a 12.5% prices savings might not compensate.
Another thing about "food out of a box" restaurant is that the box might not have the flexibility of a human preparer. If you need to change your menu, you might find you have to do expensive retooling on your box rather than a quick retraining of your employees. If you have to close a given restaurant, you may find no one wants your box. You may find yourself more dependent on your small number of box-technicians than you were previously on a large number of easily replaced unskilled cooks and so-forth.
The thing is that humans are a fabulous deal once you remove the price differential. Human comes with amazing skills, often train themselves with more, supervise and trouble-shoot each other, require little capital investment and manufacture themselves. This kind of thing is a good deal for nearly everything except production at a large scale (and the most important items, cars and iphones, are going to that large scale). The only unfortunate thing from the buyers perspective is that humans have a nasty habit of expect a share of the output instead of just a bare wage. But the solution to that problem is visible all around us ... humans.