The last time I saw that number - $300k/BTC - was in 2013. There was a European silver salesman on here who calculated it based on what you'd get if you tried to fit the "market cap" (to use the term loosely) of gold into BTC.
Interesting. Gold's market cap might be a significant psychological resistance if 2013 is any indication. Back then, BTC topped out at the per oz gold price in the $1,200s. (At the time, Mt. Gox was the price everyone quoted for the 2013 ATH, not Bitstamp or BLX as is usually the case now)
With gold's summer rally bringing its total market cap to ~$10 trillion, that would put the BTC target around $500-550K!
It's a surreal experience to see numbers like that again today, when that "1000x appreciation" is more like "12x appreciation". All of a sudden it's a bit harder to dismiss.
That's for sure.