That could be tricky. When I live, a cold burrito in a refrigerator cabinet is considered to be groceries, and is untaxed. Heat up that burrito, and it's a taxable meal. Also, some non-profit organizations aren't taxed on purchases, so the sticker price is the final price for them.

You can't pre-calculate the final taxed price using the local tax algorithms as they are today. They number can't be known until the transaction takes place.

you can just list two prices for cold and hot

That would be OK in that specific instance. However, there are a lot of rules like that, and I just wanted to mention a couple.

In any case, I'm not saying that it can't be done, just that it may be a lot complicated than adding a fixed percentage to every price label.

if that is the case then the rules are too complicated and need simplifying. that is not automatically an argument to not have a rule to list the full price, but it could also be an argument to remove or change other rules that make things more complicated. the lawmakers here need to weigh the pros and cons for each.

While I agree, I suspect there’s little political will to overhaul the local sales tax system right now.

Europe manages it just fine

For a given class of goods Europe generally has one VAT rate for the whole country.

In the US the sales tax for a given in-person sale is the state sales tax, plus possibly county sales tax, city sales tax, and sometimes even special tax district sales tax.

For remote sales, it is similar except the tax is computed using the buyer's location rather than the seller's location.

If they can calculate the price at the tills, they can calculate the price for the labels on the shelves, or the price stickers

They can do that but that costs money so they never will. We worship the dollar like its a god above gods. No way we're going to willingly do something that costs the rich a dime more than absolutely necessary.

But they cannot calculate price on ads. Also, can you deduct VAT from your taxable income in Europe? Sales tax in the US is deductible.

VAT is deductible if the buyer is a VAT registered business. The amount of VAT is still printed on the receipt by law, so you can still know how much you pay.

Companies already manage seperate ads in the EU for language, currency and price discrimination reasons, it's really not a huge bother.

So customers cannot deduct VAT from their personal taxes... I also doubt that separate ads per township are common in EU. For example, in Los Angeles the city is made from several separate townships with different sales taxes, two shops on the same street may have different taxes because one can be in LA and another in Santa Monica.