

How does it work? Why don’t supermarkets just ask a million for a loaf of bread? More money and profits, right?
Now, I am aware there are cartels and other anticompetitive practices, but no single supermarket chain has a monopoly. There is competition, the margins in the business really are not that high, and supermarkets can and do lower prices to attempt to increase their market share. In fact, for products like bread supermarkets often deliberately sell them at a loss.
Would supermarkets like to put the savings of self-checkout in their own pocket? Absolutely. Can and will they, on the long term? No. If businesses would always pocket such savings, then margins in the entire economy should tend upward over time, and they simply don’t.
Yes, I am aware there are cartels and other anticompetitive practices. I said as much in a comment on Lemmy not long ago - with some detective work you may be able to find it.
Obviously. And what they can get away with is profit margins up to a certain limit (assuming no monopolies, and at least moderately effective anti-cartel measures), that limit being the point where it becomes easy to enter the market or undercut a competitor, gain massive market share, and still make a lot of money.
They cannot get away with just endlessly taking all profits from productivity gains. These gains have been enormous since the start of the Industrial Revolution, and in most markets profits are on the order of a few percent of turnover, if that.