FYI: One of the experiments the OP explained all that time ago is STILL happening to this day.  I created my own database and saw these three transactions fly by just in the last few days:

1Kfayq6DeA5SztT79nmX4LFwG2bWmZwYKE derived from txid 40f087dd977495465c75f433772d4f7d07084d3933c4a444198403935f40ceea
19PBWUGcTt4QDi4sCtaogBsn4q58EXKUE8 derived from txid 1d613bce91a4087d78d671442710367350d24e01949d880a81c4a97edfa92a99
1Gs3BeD1TdB85aSy8xvyPegQYaPJUMo2so derived from txid 27c0e69e629658c264da83391b5ab2ccee10ecd357d4da2b4b0e52cd9d7faa9f

(That last one is for 0.11959621 BTC which is over $3k USD at today's prices)

What's amazing is that you can have the private key for those addresses MONTHS in advance of it being used.  Those txids are sometimes recorded in the blockchain way in the past.  To be clear, this isn't an exploit.  I think there is some system out there that possibly isn't initializing memory (or something).  So they seem to be creating private keys based on the occasional information found in the blockchain, probably because they are processing transactions and that's what happens to be in memory at the time.  But you'd think that after all this time, someone would notice BTC going missing.   They get swept instantly though, so good luck trying to capture them.