> When prices change, people change the shelf label

This isn't free. That's someone's time and energy spent on something I, as the consumer, don't care about. Why? I'd much rather have that person available to help, ready at the counter or frankly at home or in a park enjoying their life.

What has meaning for you doesn't for me. I don't value having a precise price at selection versus purchase. At all. Like most Americans. That doesn't mean I don't see the value in your argument, just that I reject it as something that matters to me.

> What seems 'bonkers' to you has been standard practice in most of the world for decades

Not remotely comparable in terms of rulebook complexity. Also, income: if you want to find tax-inclusive round pricing in America, go to impoverished neighborhoods. There, every nickel counts and folks pay cash--it makes sense to spend the effort to precisely message pricing ex ante.

Also, in most of the world posted prices either aren't a thing or are completely negotiable. Haggling at the point of sale isn't a thing in day-to-day America.

I concede that my other comment saying "there's no reason for it not to be [included in the price]" is inaccurate, cause this is a reason. But also, how often does sales tax change that this is a real issue?

The workers at a grocery store are already spending time setting and changing price labels across the store on a regular basis. (Such as for the many changing sales most stores have.) They often have a digital, hand-held label printer. It would be extremely simple for that printer to just print the local sales tax on the label.

Not to mention the vast amount of online shopping Americans do, where it would be trivial to include a local sales tax. (Every online store I'm aware of already immediately asks for your location and tells you to search for the nearest location anyways.)

I also reject the idea that most Americans wouldn't value this. I would bet money most Americans would prefer it -- they just aren't aware that other countries are capable of doing things better.

> This isn't free.

It's not free but it is negligible relative to routine relabelling. How many times do you think the tax rate changes per year? Maybe twice, at most, if the government budget is facing some major upheaval. More likely is every few years. Compared to the number of times the store will put things on sale or change the prices, that is negligible.