Plot For A Film
Film Plot: this claim and legal battle is just a trick to get the real Satoshi Nakamoto to reveal his identity.
Once that happens, the quick-action special ops teams on stand-by for an organized crime syndicate go into action, kidnapping the real Satoshi, with the plan to intimidate or torture him into handing over the keys to the $4.5B worth of BTC.
Like all big heists, the mercenaries each get a payout, but the main portion of BTC disappears, being immediately broken up into smaller amounts and distributed to thousands of wallets.
The authorities are now faced with the uncomfortable choice of either shutting down the cryptocurrency entirely, to prevent the (latest) crooks from profiting from the theft, or else engaging in the enormous task of trying to trace what is designed to be hard to trace, as the money is laundered through ever more transactions, a difficult if not impossible task.
The authorities know if they simply shut the cryptocurrency down, e.g. by declaring it illegal, or by freezing the blockchain and halting any further transactions until the mess can be unwound, that thousands (millions?) of small investors (speculators) will lose access temporarily or maybe permanently to their money and scream very loudly about it.
The organized crime syndicate hopes the authorities will decide the lesser evil is to let them get away with the theft. After all, they routinely pay people to steal valuable art work from museums, and then hide it in secret warehouses, waiting for the statue of limitations to run out. Even if that might not happen in the lifetimes of the current bosses. Eventually the paintings turn up again and can be auctioned off, back to the museums or to rich private collectors. Cryptocurrency is just another commodity for them.
Sherlock because it will all be a big mystery...