look im just saying, the only reason why people think btc can go to $10000 is because if enough people start using it so much that it becomes accepted everywhere, such that the only reason why it would be worth $10000 per BTC is because fiat would become essentially redundant or worthless.
I don't think so.
If fiat would become redundant or worthless due to bitcoin success, we would be looking more into $10 000 per mBTC rather than $10 000 per BTC ($10 million per BTC)
But that would be measuring using today's USD purchasing power. If USD becomes worthless and redundant, nobody will give a mBTC even for $10 million... So in this extreme scenario you need to use another unit of value. 1 ounce of gold is quite good.
I don't see fiat becoming redundant tough. That's an extreme scenario.