All of that is nonsense.

I worked for 2 corporate retail chains that would send the stores the price labels for sales and we would print out a file for other tags.

In a quarter, most labels would be replaced and they would send irregular price changes every week. We would spend probably 10 man-hours a week taking down and putting up labels under typical operations.

Items don't generally move far or often, except for rotating display spaces at the ends of aisles for promotional items where every tag changes. Every few years they might make radical changes to item placements, but they tend not to because it confuses customers.

There is no reason to exclude the tax in the price labels except for tradition and/or concealing how much you will actually pay with the tax added. Most people know what the taxes are in the area they shop and will just round up to the next dollar or add 10% if they are on a budget.

Bring on wireless electronic price tags that show the price including tax.

Meanwhile, electronic price tags have been introduced in the market.

It's these small e-ink devices that are tethered to a central input station in the backroom, where a person inputs prices.

I've seen tags change in front of my eyes, updating price, adding promotional info or changing the product available on shelf.

Inventory movements are not an excuse, I'd say. Regardless the end sale price, if a product is not sold, it is just inventory, which value is fixed for the company.

Lidl moves tons of non perishable inventory from central wharehouses to stores, daily, and they could not care what the end price was at the store. A given item may cost an X amount in a given season, disappear for a couple of months, then return to the shelves with a different price. The inventory value does not oscilate.

I've not worked in retail in over 2 decades, we printed all the price labels at the store back then and we have a universal VAT rate across the country meaning they could have done it centrally. I don't think the UK is over 30 years more technologically advanced than the US making that impossible.