To my thought, I think after the rise of bitcoin in 2017 people came in and the market grew , then in 2018, people withdrew and this is why the bear has continued. The market is still waiting for inflow of money pumped in for another major pump.
Or shall we say that the bubble had popped out that time and lots of investors losing out bigtime into their stashes.
Reason for Dump? Huge sell off or purely manipulation.It neither on the two and this had always been part of the risk of this kind of market.