But the problem is that right now a supermarket chain can advertise in the newspaper that chicken breasts are $4.99/lb at all of its nearby locations.
If sales tax were included, you couldn't advertise prices at all, because they might be different at each store!
How could Apple advertise the price of a MacBook, when sales tax is 0% in New Hampshire, but 8.875% in New York City, but 4.5% in Yonkers just north of NYC? That's a price variation of around $100–200.
You already have to produce different ads in Spanish, Italian, German, etc. So it's not really any extra work to have different prices in each.
Plus you're only dealing with tens of countries. There are literally thousands of distinct sales tax geographical areas in the US.
That may not be super sensible, but it is how it works. A business on one side of the street may have to collect taxes at a much different rate compared to a business on the other side of the street.
Attempting to maintain the same final prices in one town with 3% sales tax and a neighboring one with 8% sales tax simply isn't workable.
Individual items can have >100% markup, there are items sold at a loss to ensure you can complete your trip at a single store or get you in the door or whatever, and the store absolutely has to consider how revenue (not just line-item profit) plays into things to balance out rent and wages and whatnot. 1-3% profits for the store don't imply much about what you need to charge to offset the effects of sales tax.
As a brief example of irrationality, last I checked, on like-new iPhones it made a 30% difference in total revenue to offer "free" shipping rather than split it out as a separate line item. People would really rather pay 1.3x with "free" shipping than 0.8x base price and 0.2x shipping.
Somehow this all works magically here but in the US it is impossible because.. reasons unknown
You're drawing an unwarranted conclusion that just because not all prices are coordinated, therefore none must be.
If you consider that, I believe your reasons unknown become reasons known. No need to resort to magical thinking :)
Also it's not just about the hotel location, but also changes depending on the buyer's location -- which of course often isn't known until the checkout process.
So maybe it's not quite so simple, with so cartoonish a villain, as you assume.
If European countries chose to have VAT that varied geographically within a country, they wouldn't be able to build it into the price either.
Why you think it has anything to do with "national intelligence" is quite beyond me.
That clearly shows rates varying between countries.
Not within a country.
Which is fine, because prices are generally advertised within a country, not Europe-wide.
The US doesn't have VAT, it has sales tax, which varies geographically by a great deal.
And advertised prices in the US virtually never include sales tax (in large part due to that variation).
Hotels and ticket brokers aren't getting any kind of free pass, they're advertising prices in the same way as everywhere else like the grocery store or clothing stores -- at least as far as sales tax is involved.
Literally the only locations I've ever encountered that include sales tax in the price are a tiny minority of coffee shops (often cash-only) and budget pizza places (often the dollar-slice ones), which is to avoid having to deal with coins.
(The article is about other fees though, which is a different subject from sales tax.)