Bitcoin isn't capable of handling the transaction volume that's necessary to become a currency or medium of exchange. And to the argument that some holders aren't willing to sell at any price, there is a sizable portion of Bitcoin that cannot be sold at any price because the holders lost access to their private keys.
The ultimate problem with holding any cryptocurrency like Bitcoin or Ethereum with the expectation that this technology is the future medium for financial transactions is that a new cryptocurrencies are being created for commercial use. Just like Facebook created Libra, credit card companies, the Fed, banks, etc. can all build their own cryptocurrencies that work for their specific needs. The technology definitely can make transactions like international wires and real estate closing which currently take several days (or weeks) to complete and make them as quick running a credit card. Ultimately, that's a boon to the banking industry, bank customers, regular people sending money across borders, etc. but it's tough to see how that translates to a higher value for Bitcoin specifically.