This is how the system works and those who are billionaire today have got bought in the start or buy huge qty when market dips and not when the market is rising or at high. This is the difference between a normal investor and the billionaires as they can forsee and capitalize on it.
Well it doesn't seem that the big investors are making a move just yet since if they start buying we'll be able to see a run. I don't know if they're still waiting for a lower value than where we are now. But eventually they'll come back, i'm quite positive about it.
actually many of the bigger investors buy bitcoin off the market for many reasons such as not wanting to push the price up while they accumulate at a good discount, or some may be even trying to not leave a trace behind for the government to track as they dump their fiat for bitcoin silently.
and the whales that are on exchanges aka the market makers are not letting the price go up by dumping bitcoin as it tries to rise. so they buy at a fixed and low price.