-snip-
then the question is what will make bitcoin recover and can have high prices again?
I think he is right partially. Instead investors focus on Bitcoin only, now they invest in other alcoins. That makes the market cap of bitcoin decrease significantly.
In my opinion, $20k is not the real value of bitcoin, because this price is reached by FOMO effect, at least in 2017. So I think the current price is not a "low" price as we think.