Do you know how long it takes someone to sign up on an exchange, go through their KYC process to verify their account, make money transfer from their bank account to that bitcoin exchange, wait a long time until it reaches the exchange and is credited in their account and then eventually after jumping through all the hoops they can buy bitcoin?
Though I don't have the data to back this up, Robinhood(which has had cryptocurrencies for a while now) has a crap ton of users and trading volume and I definitely don't think we should be underestimating the potential buyers from that platform alone. Also take note that we're talking about Elon Musk here, which is pretty much WallStreetBets' lord and saviour.