I agree with Akito that the creator of this puzzle moved out puzzles 120, 125, and 130. I have been researching this topic for a long time, and based on my analysis, just after puzzle 120 was solved on 2023-02-27, the creator increased the prize money to a total of 1000 BTC on 2023-04-16. This seemed to be a public stunt by the creator to draw more attention to the puzzle. Then, on 2023-07-09, puzzle 125 was removed again, likely as another public stunt to generate further discussion and speculation that someone had gained the knowledge to crack ECDSA within a 3-4 month period. After that, when puzzle 66 was solved and subsequently stolen by another pseudo person (I’m unsure if this was also a public stunt), the creator quickly moved btc of puzzle 130, likely to attract even more attention.
I don’t mean to offend anyone—this is just my analysis. Everyone is entitled to their own opinion, and this is simply mine. I have no intention of offending anyone.
This could be true but from the other hand why he would do that ? You said his goal is to draw more attention. I don't think so. This whole puzzle thing is very niche topic, normal people don't care whatever he will do here... and moving puzzles like 120 125 130 and 66 makes the whole thing even more unaccessible to average person due to obvious hardware limitations.
He stated clearly what this "puzzle" really is: it's meant to measure what can be cracked at current time, He doesn't care who takes the bitcoins or how it was done or if someone stole the transaction. All he cares about is current cracking capabilities. As if someone is monitoring if increasing bitcoin security is necessary.
I think the "creator" is not a random private person. It represents someone who have important goal in knowledge how safe bitcoin is currently. This is someone who created BTC, big exchange or something like this.
How many people you know that instead of cashing it all or at least holding would make a puzzle and play such game ? And if someone has thousands of bitcoins and this is just a part of them why would he even bother to make such puzzle ? I tell you it's not a single private person and he is not moving the puzzles himself.