We have to understand how many years that made up of the decade he predicted and do some comparing with the price of Bitcoin now, so actually he is talking about a period of ten years from now to see the Bitcoin possibly at that price and this is something knowledgeable because the impossibility of it is too minor and Bitcoin always have the capacity for unexpected growth, although having a recent pullback is not something to affect his prediction because there are still a lot of time, although i cannot say he is completely right but i believe the price might not be far from his calculation in ten years from here.
The end of this decade will be 2030 and Bitcoin will experience just one bull run. The price of Bitcoin is determined by the force of demand and supply, thus hitting $500k is possible depending on adoption. If more nation states and corporate organisations keep investing in Bitcoin, the price might get to that level by the end of the decade.
The pullback Bitcoin is going through now is insignificant; it's just an opportunity to buy at a cheaper rate. Nevertheless, everyone can predict but we have to wait and see how this will turn out in five years.