Nobody is foolish enough to buy high and sell at low rate yes there were some correction in the btc value but i don't think that the investors will be that foolish enough to buy at higher rate and sell them off at lower level.But it does not mean that it will never happen .There are some people who bought btc when the price hit 20K as they thought that the market will will go beyond that but the ban on the ico's in china and ban of btc in south Korea hit the market as there were high number of user of btc from China and S.Korea and lot of investors started doing panic selling when the price hit 20k and it has also affected the btc market.The new investors also did panic selling when they found the price hitting low as they thought that it was the end of btc market but it has been proved wrong even if the market falls it does not take much time for it to recover and the Ups and downs in the market is something which is normal in every market situation.