That doesn't answer the question lol. Fiat has been around longer than BTC. Its worth is "Trust me bro" from a gov.
Now using your logic, one BTC is worth 0.00001 XMR then. BTC is priced in XMR using the logic provided by you. See how that doesn't make sense claiming fiat is priced in Bitcoin. I live off of purely Bitcoin and even I know that's not how Bitcoins value works. 😂