[OrwellianChild]

It might help to think of this like a "Reserve Price" on an auction. The listing price illustrates the lowest price at which the seller will sell with no questions asked. This doesn't mean they can't sell lower - it just requires negotiation. Likewise, if there are multiple competing bids, it clearly has to go to the highest bidder.

There are instances of this kind of price movement in commodity products too, depending on demand. A rapidly selling product will get a bump to its MSRP, while the introduction of a competitor will cause price competition. It's not all that different in methodology - it just moves slower.

Be grateful that your local supermarket is no longer a street market, where each price has to be negotiated and haggled. Price discrimination there is rampant, so each buyer gets a personalized price tailored to extract as much as possible while still completing the sale.