Yes because if millionaires come together and buy huge volume of Bitcoins then the Bitcoin community will be dependable on their actions. Let me just say they own half of the total supply of Bitcoin then every single transactions they have to make will trigger a pump and dump depending on what they are doing with their Bitcoins and they will be called whales who are now able to control the flow of prices on the market but I don't think they will do that just to manipulate the market since it is risky too but that could possibly happen and will surely make some more profits to them of course.  If they will then they can because they are millionaires or even billionaires.