The main argument here is that at its current state, you have to invest not-so-small capital in order to be part of the bitcoin production system. If no one puts capital, no bitcoin will be created. In this regard, bitcoin is different from all other cryptocurrencies, including Ethereum (Yes, Ethereum also uses POW but there new blocks can be created much faster with less capital intensity). This has nothing to do with 21 million cap or scarcity.
The main argument here is that at its current state, you have to invest not-so-small capital in order to be part of the bitcoin production system. If no one puts capital, no bitcoin will be created. In this regard, bitcoin is different from all other cryptocurrencies, including Ethereum (Yes, Ethereum also uses POW but there new blocks can be created much faster with less capital intensity). This has nothing to do with 21 million cap or scarcity.