Don’t believe you were what you say you were. Your exposition does not support anything other than a beginner’s grasp of how taxes work.
Now move along and find someone else to try out your spiel on.
LOL Even if you don’t believe me, which I’ll be happy to PM you my LinkedIn profile if you like (I’m now a finance exec in the hospitality industry), you could read the article I linked you or search for any other number of sites on how the VAT tax in Europe works. Of course taxes are always more complicated than that (do you know how hard it is to keep track of the taxes you need to collect for 20,000 items in ~30 states and in 150 counties? Some states/counties have different taxes for baked in house vs down the road, some have different tax rates if you are over a certain age, you can’t charge sale tax on WIC and EBT purchases, etc) but the basic system is exactly how I - and that article I linked you - described it for both the US and Europe.