I don't actually believe in prediction even it came from a crypto expert. What i believe is that cryptocurrencies are very unpredictable as its market value is based on the supply and demand of people. I don't think anyone can ever predict someone's mind whether he/she would like to invest in crypto tomorrow or not.
The predictions that we see are mostly done by either shills promoting their altcoins or analysts providing technical insight. If you are into TA you can yourself predict much of the market movements once it starts.
People dont make predictions before the movement starts but only after it starts. Same with every stable period - they will say its either going up or going down - nobody can deny this. Thats how these predictions work. In fact most of them are just to keep the public happy and not provide too much speculation.