If it were that simple, Vanguard wouldn't have taken the additional step to prevent trading in these products on their brokerage. Telling customers "you can't buy Bitcoin because we can't sell it to you at a profit" would be ridiculous.

Do you think Vanguard has any reason to lie about their motivations here? Do you think their S&P500 MF/ETF distinguishes itself in any way from Fidelity's or is a motivating factor for having one? This is just a bizarre conspiracy theory to espouse on the basis of no evidence.