It is worse for online where until you log in they have no clue what taxes will apply. If you are buying a gift for someone in a different area I don't know what tax rules apply but there is good odds they won't know until you get to the shipping information what the real taxes are.
And if you can do that, then you might as well print it on the price tag (along with pre-tax price if you want). No buts.
Ditto for online, after you get the customer's ZIP code.
They literally can't know the price until you tell them whether you'd like a fork with it.
Now, this restaurant works around it by having both prices listed, but I can imagine a million freaking variants of that for an online sale: "you have to pay our local taxes, but almost maybe yours, unless you check out on a Sunday between noon and 5PM, which is a tax holiday on your block (but not your neighbors' across the road), so understand that the price may change between when you add it to your cart and when you click the 'pay' button."
I'm only a little bit exaggerating.
There are zero legitimate reasons not to show true prices.
Fun fact: sales tax rates are not stable. Our state publishes quarterly tax changes at the county level; city-level changes are presumably too numerous for the state to publish in the same format.
Inclusive pricing can obviously be done in-store, but it also more or less ensures that some of the items in your store will have incorrect prices some of the time.
The legislation in most of europe clearly handles this - the price displayed is for the intended customer. If you go into B&Q (home depot equivalent), you'll see prices including sales tax. If you go next door to a timber merchant none of the prices have sales tax included. If you're a business, you don't pay the sales tax. The businesses know what their taxes are, and are required to have accurate accounts anyway. For those that are maybe numerically challenged - they'll never pay more than they see on the sticker.
> It is worse for online where until you log in they have no clue what taxes will apply.
Enter your shipping address to see pricing. Exactly the same as it is now. Give an estimate based on IP. Exactly how it works in Europe, which has the same problem.