Well, it is still just his own opinion and market manipulation and maybe he is right but never I should believe that because 4 years from now, that might be another bear season. Unless, if he will say 2 years from as halving will come during that time and expect Bullrun. Honestly, $68,000 is not quite too high but if we talk about $500k in the next decade, I can't imagine that price, it was overpriced and it was impossible. Imagine, $500k is too expensive and I can't say who will be able to take the risk from that price.
Based on being an investor, I don't think he's trying to manipulate the market like Elon or any other shark. His prediction is just an unbiased view of the market as he has not sold any bitcoins since holding, not only has he not sold, but has continuously DCA during periods when bitcoin falls further.
Based on what is happening with bitcoin, widely used and adopted by many large companies, many countries and has become legal in two countries El Salvador and Central African Republic. Then we can think of more countries that will accept bitcoin and the $500k price point is also what I want it to achieve.