the main assumption is that everytime he debugged his client and updated it, it created a new wallets/files and be didnt back up the previous
take this quote that shows early versions needed backing up entire folders.
imagine backing up a folder every time you edited a line of code
4. What files need to be backed up for not losing my "money"? Only the wallet.dat or the whole Bitcoin AppData directory ?
Version 0.1.5: backup the whole %appdata%\Bitcoin directory.
Version 0.2: you can backup just wallet.dat.
satoshi's 'stash' were 50 coins per address which if 1mill coins was accurate would be 20,000 addresses, in numerous folders, if he did backup
remember from january 2009-mid 2010 bitcoin had no value in the real world. it was just a experiment back then so there was no value in keeping the private keys. assumptions were that after a few months of bug fixing everything would be reset and born again. but too many joind and it instead just continued to live and it wasnt until 2010 before h made it simple to backup
extranounce patern that sergio provided in 2013 shows that around 740,000 btc were mined by satoshi ,After August 2009 the pattern breaks down to some extent, there is no other evidence that show pattern still same after that
i think other coinbase unspent will remain unspent because thoses are mined by random people that never have backup of wallet and just tried satoshi client for while then deleted it because btc have no value in 2009 so its boring to keep mine for some cents
of course satoshi may keep mining it but there is no proof for that yet and we cant say satoshi own 1m btc
some people claimed that they mined a lot in 2009 but non of them signed messege as i know i only believe hal finney mined some blocks
after 2017 20k$ price every dam trader could sell 2009 mined coins to be rich as hell . so thats the case only satoshi coins remain