Nah that's insane! Even $100k in 3 years would an outstanding performance.
On the other hand we've never seen something like that before and high price levels may be possible, at least for a short amount of time. I expect definitely a 6-12 months bear phase within the next 3 years. So no price rise, just retracing and consolidation during that period, whatever the top of the actual run will be. Therefore $500k is very unlikely to happen imo. But this price level is possible! Just not in that very short timeframe of 3 years.