If people buy Bitcoin at $8,000, they will get 100% profit only when Bitcoin reaches $16,000. If it takes 5 years to reach $16,000, people will earn more money from Gold and Silver than from Bitcoin. Silver is giving 20% to 35% profit in one year.
Mining cost of one Bitcoin is $5,000 or more. When Bitcoin was $400 or $800 it was understandable because people had to just spend $400 or $800 to get one Bitcoin and $1,200 is super high profits when Bitcoin started from $1.
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https://www.quora.com/Why-do-people-still-invest-in-Bitcoin-when-the-days-of-striking-rich-have-already-passedPersonally, I think that people have this belief that despite the high price, Bitcoin still has the potential to grow further as demand continues to increase. But there may actually be some truth in this especially for the big players. For the small players, probably not so much.
People still believe in Bitcoin because they trusted it. It will rise even the market is in red status. Bitcoin has a future to go further in the cryptocurrency world market. Greater opportunity is coming to Bitcoin that's what they believe.