Bitcoin is going mainstream, millionaires massively investing in Bitcoin only because to increase the price of Bitcoin and get media attention to make it mainstream.
i am not sure about this because if millionaires wants to investing in bitcoin, i think they will do it without giving any statement or make press conference because they want to act like ghost, act behind the layer, and they don't want to make every one knows that they make investing. beside that, i think millionaires just want to getting profit from increasing bitcoin price and they will get it because they have big fund so they can easily to buy bitcoin in much of amount.