That's a weak justification to apply to prices listed right where the product is sold. Like, if one uses a sticker gun to put a price tag on a product itself.
I don't know of any US businesses other than waffle house that always include all taxes in the listed price, however.
There are laws against adding in taxes on listed prices in places like NJ, likely others as well.
Regardless, I'm not sure why people consider it such a big deal. It's consistent across the board and it's relatively basic math to estimate what the total would be.
I've lived in places that do it both ways and it's a non-issue.
Hard to advertise to a wide audience when the final price after tax is one of 12 different prices depending on where they live.