About 10% of Bitcoins were created early, before 2012, and have never been traded. If somebody ever finds the key of the early lost Bitcoins, they'll have a huge payoff, over a billion dollars. Speculation is that either "Satoshi Nakamoto", whoever he is, is holding onto them for a big payoff, or somebody lost the private key for all those early Bitcoins. As the years go on, the second explanation seems more likely.
Gaining access to the early wallets and bringing those Bitcoins into circulation will lead to a crash in Bitcoin value due to both increasing the supply (as in https://en.m.wikipedia.org/wiki/Spanish_Price_Revolution?wpr...) and decreasing confidence of other Bitcoin holders in the security of their wallets. You could extract some portion of the value if you do it slowly and pretend that Nakamoto is using his wallets, but you will not be able to extract their current market value.
While agree the increase in supply would drop the price I don't think the Spanish Price Revolution is analogous . . I think that's more analogous to what cryptocurrencies are doing to the Dollar.
How would you sell that many coins to guarantee maximum payoff? Surely getting access and attempting to sell Satoshi's stash would trigger a massive panic in the market?