Bitcoin is decreasing considerably right now. So it is the best time to buy right now and hold it. Keep on buying little by little. When bitcoin price goes up again the law of cost of averaging will definitely make us earn. Bitcoin wont disappear because it is the foundation of all the altcoins in the market out there.
I agree with that bitcoin won't disappear. Actually, many investors believe that bitcoin has a lower falling risk, compared to other currencies. This is because bitcoin is a global currency that does not depend on government policy that can fail and cause hyperinflation or complete collapse of the exchange market.