This is a really interesting point and got me thinking — if taxes were hidden, people wouldn’t directly notice the cost increases associated with raising sales tax. If you pay $1.12 for a $1.00 soda in city one, but $1.07 in city two, you will directly realize the tax impact that the local sales tax has.
I wonder if this was originally intentional, to prevent taxes from invisibly rising without the people being aware of the impact of the price.
It also makes it much harder for national brands if they like to have nice round numbers as the cost of things (which they seem to) - they can’t charge $1.00 for a soda everywhere, or their margins would be crazy wonky depending on region