I can spend that in whichever tax jurisdiction I want and the VAT rate might be whatever depending on what one buys. If you want to go that route you'd then also have to adjust for cost/quality of living to stay intellectually honest, which means you'd then have to come up with some statistical consumer basket. It's a stupid idea to even start down that route in what fits into HN comments.

Do you pay VAT on almost anything? It affects how much your actual disposable income is and thus literally how much you can purchase.

Nobody said its going to be trivial to calculate, reality doesn't care about that.