If you buy a bitcoin in the price of 9000$, yes it may drop, but we have clearly seen that this is what it does. It goes up and down. If you have 1 million dollars and buy 100BTC (900.000$) then the only thing you have to do is wait. Because someday it will pass that number and you will have profit. Am I wrong?
Just practical, people are just afraid to invest in bitcoin because that market could easily be a dump and they just never know if the market is going to recover anymore.
Also investing in bitcoin is going to take time before you could earn a profit if you're unlucky for example you're going for a long term investment a lot of people is not going or cannot wait for the market make the pump so every investor is considering selling their investment even for low profit or even if they already lost money they just pick not to invest because it was just as risky or they selling their investment because the market is already dumped and afraid of losing a lot more.