You can dispute it in the case of some hypothetical future architecture that requires physical real world enforcement of some state change on a decentralised ledger, sure, there you might have a point, who can say what the future holds?

That's not the same as denying access to global markets, as long as legitimate cryptocurrencies maintain liquidity with global markets, that attack can be ruled out if you self custody. It doesn't rely on any physical state, it relies on you using a centralised service of custodial account management where a third party can direct that entity to deny service to you, or that service can independently decide to deny service to you. There's no centralised service to attack in a proper peer to peer system, they can't stop you interacting with the market.