This is mistaken. There is the cost in labor to replace signage, and the delay in time for that replacement to completely occur, as well as the regulatory required related to signage.

The point of sale is bound to the signage price. There are laws against bait and switching, and other deceptive business practices where electronic instantly updated prices would fall afoul when they get to the register and the mechanics of a bait and switch are in full force (violating law).

Online orders following dynamic prices also run into the same issues.

Dynamic pricing is just bait and switch pricing, and the courts will eventually confirm this. The method adjusts the price upwards when it shows more demand (as they claim), and they define demand as the number of people visiting, or more accurately the number of clients connecting. This can be sockpuppet clients of a vendor that algorithmically join to boost the price like any shill.

I've seen this happen with items where they adjust it up 15-25%, and don't show that adjustment till after they've charged you. 15% for a $10 item is a lot less than 15% for a $1300 item. Would you find it acceptable if they just tacked on $195 in surge pricing or more.

To understand this clearly, you need to understand this isn't demand. Demand as a cohort only includes the number of people that would make an exchange at a given price level. What they are actually measuring is a Need cohort, and they misleadingly conflate and assume that this is demand because it is in their interest so they can charge a higher price deceptively.

A Need Cohort includes all the people who will not make that exchange. That's everyone that visits and leaves without purchasing, and in reality, its the entire population that wouldn't purchase the item but would find some marginal need for that item if they had it (including the entire secondhand market).

Consolidated monopolies aren't about screwing customers out of pennies. Its all about screwing them out of the percentages based on the goods they sell, and what they think they can get away with given their position which is capable of holding a geographic region hostage.

For an example, the Egg price fixing where they claimed they had to cull all these birds because of avian flu, they raised the egg prices to roughly $15/dozen, and somehow produced more eggs than birds alive in the same time period. The same thing happened with expiring meat where the meat manufacturers negotiated a lower-price buyback for all expiring meat products to limit those loss lieder sales making it to the public. It was speculated the meat was repurposed/processed and sold as pet food.

Price discovery for goods has requirements that must be met, and aren't met under monopolies engaging in dynamic pricing. There are also well known methods for identifying price inflexibility in demand which do not include price confusion.