If maybe we are talking about 10 to 20 years, then it is possible. But we are still at $9k and three years to cost btc $1mil is a bit impossible right now. The author also indicates this corona pandemic as the new way of changing the system. I am vague on that part. If that affect the way people invest in bitcoin, etc for btc to reach that price, I still see it inaccurate prediction.
That can happen if the adoption process is fast, and people realize that bitcoin is worthy of buying, especially if the price is down a lot. Just hope that in three years, the adoption process will grow and reach more people in all countries, so that can lift the price. No matter if the price now is hard to increase and break the higher price, we will see that happen in the future. There are many predictions about the price of bitcoin for the future. But that is the prediction without we know if that can happen in that year or not. The important thing now is we should have to try to earn more and more bitcoin before the price increase so high.