I think this also has some interesting implications for real estate long term - if every mcdonalds needs 50% of the space they currently occupy over time that real estate will be put back in the market, multiply that by every organization doing that and it has some follow in implications that I can't forsee but find very interesting.
OTOH, the nice dining experiences will be done by people who can improvise and improve day-to-day based on their own tastes. eventually, the stuff people do will be the "good" stuff, and the stuff robots do will be the "bad" stuff. Hopefully. A more negative viewpoint says that robots will do the "high value" stuff and the people will only do the "low value" bad stuff.
In fact, if you consider the partial oxygen pressure (which is what matters for your lungs), this air is no worse than the air you find inside an airplane, or at a 2500m (8200 ft) mountain peak; Wikipedia says 140 million people live permanently at above 2500 m.
Now, this already exists and is called a hypoxic air fire prevention system, and is used e.g. in some data centers and in archives of valuable documents. It's not used in fast food restaurants though, because they have better ways of preventing and extinguishing fires at lower cost.
The majority of space in a McDonalds is the dining area and ordering counter area These areas are occupied by customers. The kitchens in a McDonalds is already pretty compact and dense.
I mean, real-time voiced-over translation on Skype? Eventually even mimicing the other person's voice? Yes please!
All thanks to this shallow form of AI that Nick Bostrom coined as "artificial narrow intelligence" (as opposed to "general" intelligence, i.e. human-like; and "superior" beyond ours). It's becoming possible for businesses of all kinds and all trades, thanks to the drastic cost reduction of deep learning since we moved these tasks to GPUs (and these bad boys keep improving at +25% performance per generation roughly every 18 month). And what AI does, sometimes is order of magnitude better than what any human individual/team could do (think Spotify's recommendations, anything with "big data" and "subjectivity" in it).
Which leads to the same conclusion as your last sentence.
It's orders of magnitude more scalable but you're music nerd friend will beat Spotify's recommendations any day.
Second of all, following their links we find that in 2012 they had a full scale machine built that had a 95% success rate, and they projected 11 months until they could launch the concept in a restaurant. What has happened since? No word, AFAICT. Happy to be corrected if I missed it somewhere and they have actually launched.
But otherwise, it doesn't exactly convince me this is "the next industrial revolution" if they can't polish out that last 5% of a single-purpose burger-making machine in almost half a decade.
A more concrete if less evocative example is Amazon's warehouse automation. Relatively simple robots with 3 DOF (2D planar movement + a container jack) are wiping out enormous numbers of jobs, both in obvious immediate effects (less fulfillment center jobs) and by decimating conventional retail.
edit: Momentum still has 19 employees on LinkedIn, so they're not completely dead it seems.
Let's assume your robot arm example is about a frycook at a burger joint. I agree a robot arm isn't an effective way to replace the frycook, but a specialized system like Momentum Machines is developing[1] will be.
The automated fast food joint isn't a regular one with robot arms instead of people, it's a box the size of a small office that takes raw ingredients from a stockpile inside of it and creates fully assembled burgers, fries, chicken strips, and onion rings without any human interaction.
Automation hardware will strike a middle ground between specialization and reuse. Eg the deep fryer will be able to cook several different meals, but it will still only have 1-2 degrees of freedom for putting stuff in and taking it out. Similar story for the grilling surface, veggie chopping system, and the plating / packaging mechanism.
This is much cheaper, faster, and more reliable than truly general purpose robot arms. More importantly though, it takes dramatically less space than a conventional restaurant, so you can plop your company's food-making-box down in Times Square and actually make a profit, while everyone else is stuck four blocks away to break even on the real estate.
The stories will be different in different sectors, but in general I think the coming automation wave is a bunch of quantitative changes coming together to form qualitative ones like this. You could probably build a burger-maker a decade ago too, but the hardware and design know-how necessary have gotten orders of magnitude cheaper and more abundant, and so now it's actually happening.
[1]: http://momentummachines.com/