> If merchants across the world make a deal with me to charge exactly the listed/advertised number exactly, no more, no less, then I'll pay in cash again.

Where are you not getting this? You mean taxes on top of the retail price? You would pay cash, if the merchants colluded with you in evading taxes?

You could just do what all of Europe does and just include the tax in the listed retail price, rather than only tacking it on at the end.