I'm not sure Japan is the best example here. My experience is that most shops have the price excluding consumption tax printed very prominently in large numbers, and then price including consumption tax is printed in much smaller writing underneath.

The price excluding tax is the only one you can read at a distance, that draws you in. As someone from the UK who is used to seeing price tags show the final price you pay at the till, I was constantly disappointed that items weren't quite such a bargain as I'd first hoped.

On the whole there are still many things that are much cheaper than in the UK though :)