This is an extraordinary claim that requires additional justification. Being first is no guarantee of long-term success. If people prefer to transact in other currencies, or other cryptos gain significant global transaction, so will go people's incentives for holding those alternatives, and down will go the trade value of Bitcoin.

The fact of the matter is, in terms of utilities than scarcity, other alternatives improve on it along many axes, and most equal it in terms of scarcity.