Can you look up the taxes in advance? Sure. Assuming you know to look for local sales tax, and county lodging tax, and the city entertainment tax. But why is that necessary? Why is it helpful to you as the consumer? Do you think the retailer doesn’t know the total price in advance?

Exactly. There's no reason any of that shouldn't be included in the advertised price. I'll never understand people who want to go to bat for practices that are at best asinine, and at worst, deliberately misleading because they place the burden of determining the final price on the consumer before reaching the "checkout" section.