I think even those who believed in the technology themselves didn't imagine that the price of 1 BTC would reach more than $60,000 someday, or else they wouldn't have sold. They would have accumulated more instead. Even Hal himself who thought that Bitcoin could reach as high as $10 million converted a lot of BTC during his lifetime. Perhaps they considered the possibility of Bitcoin becoming very expensive as remote, so much so that they didn't think twice of selling when Bitcoin was as cheap as a hundred dollars.
I think no one knows or no one are expecting way back then that bitcoin market value will going to soar high like the current price. Every one has their own kind of story of regret that they did not able to catch up bitcoin at the time that it was affordable by many but in the case of OP I think if I am in his place way back that time I will be having a second thought also even let's say I am a professional trader of stocks and knowledgeable enough about trading, aside from the huge amount of investment which a bit sound shady if we will be in that place while we listen to him, crypto platform was just new that time.