It would've been understandable if he had said 100 years, but saying 1000 years changes the gravity of the matter. It's impossible to predict how something that emerged only 16 years ago will impact the next 1000 years. Considering the speed of technological advancement, making such a statement does nothing but trivialize the issue. In my opinion 1000 years from now there will be neither the US dollar nor gold. It's even doubtful whether the Earth will still be habitable. We all believe in Bitcoin's future, that's why we're here. But saying Bitcoin will still be the most valuable asset 1000 years from now is not a claim to be taken very seriously.