When a guy like Jeff Berwick throws some shit out like that and it isn't attached to an ebook or course on buying bitcoin, he doesn't really have any economic interest in making exaggerated claims.
If I had of invested £30k when I originally saw bitcoin & thought about investing (but didn't because of some stupid doubts & now I kick myself because I knew that digital currency in the long run is the way of the future)... I Would have over £400 million, cash!! In a matter of 7 years!