My boss once said that you can abuse human workers, you can underpay them, you can worsen their conditions (and if you do it slowly) they might not notice, or they going to work even harder to survive. Worst case scenario they quit, and you just find another one "new" and repeat the cycle.
But you can't underpay robots. You can't abuse them. Why? Because they just break. You skip on maintenance, on working conditions, on anything around robots - and you are looking on fat sum of money that just going to get burnt on a new robot and its installation.
So no, robots are not going to save money, especially in this scenario, because abuse would be massive.
You do actually have to pay them more than minimum wage, if you think about it.
Minimum wage in many countries is so low it's not enough to sustain a human. You can't do it to a robot, since it will just not do its job, no matter how many regulators you capture or how many middle management manipulations you pull. You have to pay a living wage to a robot.
This is why "people are still cheaper than robots". What happens if there's a 20% wave of inflation? With workers, it's "we don't give out 20% pay raises, grow up", with robots, it's "here is your power bill, it's 30% higher to cover for any further fluctuations in inflation, pay it or shut your factory down".
Robots need breaks too, if they are not regularly maintained they will start to make mistakes, costly mistakes, and they might break, and when one breaks, you don't just recruit one more wage slave from the fucked up job market, you shell out a lot of money for a new robot.
There may be cases where the price of labor is lower than the price of a specific machine, but the Industrial Revolution was built on replacing labor with capital.
It isn't evenly spread out, but it is something increasingly happening to more and more jobs.
Obviously, automation is changing work, and you can make cheaper robots that will be cheaper than working someone to do the same thing. All I'm saying is there is a significant component next to the direct "pay vs. machine maintenance costs" question.
My point is that companies and employers have got used to a ton of leeway with workers, where they can offload a ton of risk to people just because they are employees.
See for example that one case when that US airline wanted to weasel out of honouring a deal offered by their chatbot. That's them realizing they can no longer just say it's been a mistake made by an employee, as there is no separate legal entity to push responsibility on.
The same with paying a wage lower than living wage. If they pay sub-living wages, then the onus to make up the rest needed to lead a life that enables you to work long term, thus the risk is on you instead of the employer. If they replace you with a robot, and skimp on its requirements, it will break, and there is nowhere to push the responsibility.
Money is missing from the tally at the end of the day.
In one case, you have an employee as cashier. You can reprimand them, in some jurisdictions even take it from their pay.
What do you do with a machine if money is missing? It may be a tricky customer/thief, it may be just that the machine is not always 100% accurate in certain circumstances, maybe you skimped out on maintenance one too many times. Who do you blame?
That's why there are no vending machines for certain types of goods, or no self-checkouts at car dealerships or "bad neighbourhoods". Sometimes the risk component is too high.
A return on investment of 0.5 to 2.5 years is pretty good for companies. You also have to factor the costs of maintaining a space for a human equivalent. Paying a wage doesn't cover all labor costs.
I mean, maintenance is going to be a bitch. Your going to have to pay thousands in travel fees and probably thousands of dollars an hour labor, plus whatever robit parts cost everytime it breaks down. And while it's broken down, you can't earn revenue, like you could just replacing an employee.
and it's quite a bit more than minimum pay for humans
Is it? I can buy a vending machine for less than $8000. Converting that cost to minimum wage, that is ~28 full time weeks worth of labor to act as a mechanism to sell items. There are probably a lot of times when the cost in capital is less than the cost in labor.