That implies that fiat is the source of value.

WRONG

Just because you measure Bitcoin's value in fiat terms (highly manipulated measure) doesn't mean that it reflect's it's fair value.

In reality Bitcoin is far more valuable than it is possible to price in any fiat because of its intrinsic properties:

1) easy to secure

2) easy to transfer

3) no counterparty risk

4) no counterfeit risk

5) easily programmable so perfectly suited for emerging lightspeed digital economy

it may take time for these properties to be fully priced in but we're currently undergoing this process

The only thing that are valueless in this paradigm are fiat promissory debt notes you think you own