Many people continue buying bitcoin because they want to gain profit and get benefits of using it and they believe that will help them to make their dream come true and give them a brightly future. I believe also that this will be happens if we work hard to achieve it to become a successful person on working cryptocurrency. But the time where you can get a 100x in bitcoin are over. so i think that if you want such high profit you need to invest in altcoins.
People still have hope for the future of using Bitcoin. I think when the price is growing up my own white people want to invest in it because they believe that I can earn $100 per day.
It is just simply because they are still hoping that sooner or later the bitcoin will come back and be stable as high as it is.
Also some people who enter this because they want to have a big investment that they can do so they are taking the opportunity that they can take so that it will be profitable for them as the price rise again.
People who are smart take this as a sign to have more because they have the knowledge on how to deal with this kind of circumstances.