There's a slight difference between having one tax rate at the country level and having numerous differing state and local sales tax rates. You don't even know what to charge the customer until you know their exact location.
(And in the fast food example, the customer's home location doesn't matter. The store's does.)
The juice is not worth the squeeze for online retailers. Users are used to seeing the final amount at checkout and you know, it's really not that hard to mentally estimate <price of thing I'm buying plus 10%> (which is actually usually an overestimate).
The EU has a similar smattering of disparate jurisdictions (with varying VAT rates) just like the US does.
Cool, great place to start. Let's fix that. Both have similar land mass, similar populations, similar balance of federal-ish and state-ish and local-ish governance, similar cultures, etc.
> And for what? Making the checkout process slightly more convenient for people who lack the mental ability to estimate their total?
Surely handling 13k tax jurisdictions is expensive for businesses and consumers on many levels?
Unintended consequences: None?
Prices are already quite different between online and in-person shopping.
You in the US keep saying "we are so special, so it is impossible to change things for the better in any way". While other countries also have complex rules for similar things yet they still manage to provide a better experience for shoppers, citizens, sick people - everyone.
In Germany different tax rates apply to items that you need to survive such as food and other goods. It can be difficult to know which rate applies to a product. The good thing is you don't need to know because the total price is displayed