I'm very sure even satoshi nakamoto never believed Bitcoin will become this big, Bitcoin is growing day by day and with the way Bitcoin is growing if it continues like that which I'm sure it will, Satoshi Nakamoto may one day becomes the world richest man.
Whoever put up that website or data made a couple of mistakes in my opinion, firstly it has never been confirmed in the history of Bitcoin that Satoshi is an individual hence "he's" best referred to as a pseudonymous entity since no one has 100% proof he is a single person or a group.
Secondly Satoshi's worth can only be estimated as an approximation or a variable value since you can't really tell exactly how many bitcoins he mined plus his wallets are scattered across the Blockchain. infact there is a high chance he's been spending but everyone thinks it's a random whale.