People for a long time called bitcoin bubble, called even in 2013, when it cost 35 dollars. After all, this is an unexplored territory. We still do not know how to evaluate this currency and what will happen to it later.
Even today they still call it as a bubble every time when Bitcoin started to decline the market price and drop so big. They just compare it to the tulip mania because of the sudden fluctuation of the price of a single tulip before and then later on it's just gone which brings to most investors to get bankrupt when they bought the tulip for a high price.