I have been hearing that Bitcoin will never drop to zero ,because if that happens people might buy entire bitcoins and bitcoin will finally come to an end and that would the greatest regret ever in the history of crypto currency,but what happens if it drops to zero?will someone be able to mine entire 21 billion ?
Your words are contradictory. If Bitcoin drop to 0, no one will buy it. If someone buys it, it will not drop to 0.
Correct you：
1. Bitcoin will not drop to 0.
2. The total amount of Bitcoin is 21 million instead of 21 billion, and it will definitely not be mined by just one person.