In Europe they make a best guess based on IP location, and if logged in using the account address or previous delivery address.

Then the price may change at the checkout if you put in a different/unexpected delivery address.

other countries have figured that out even countries with multiple levels of taxation like in the U.S. it's not an unsolvable problem.

> not an unsolvable problem

I never said it was. In fact, I specifically said that there is work to do before making the rule about listing all prices inclusive of taxes.

but you did say that figuring out the final price is "unacceptable"? why is it unacceptable? my point is that other countries have figured out a way to display the final prices, but USA still hasn't figured out how to do it or they don't have any plans to do it.

As things stand currently, it would be unacceptably intrusive as you have to collect information on all shoppers whether they purchase or not.

Do the pre-work first, and then make a rule about displaying the final price.