If we look at 2018, then there we will see a lot of negative news about crypto, this is different from this year, because the bear market is going fast and has not yet reached 1 year, we see a new ATH of Bitcoin being reached.
The next thing is about the number of fraudulent projects, this makes investors lose confidence as some investors withdraw their money into Fiat, at that time we see ethereum trading below $100 usd.
I didn't get much information about why the bear market happened, but from some negative information that made investors lose confidence and then they decided to sell all the coins then we saw a dump and the price was difficult to rise because the number of requests had not increased.