It's not clear that decentralization will or would save Tornado.cash.
The actual smart contract is already permissionless and decentralized. You can use it from front ends other than tornado.cash.
However, anyone who provides funds or receives funds from the mixer is now at risk. If you were previously providing liquidity to the mixer without being involved in any particular crime, there is now the risk that your account address will be sanctioned by exchanges, and it will be substantially more difficult to exchange your ETH and tokens for other tokens. This seriously undermines fungibility on Ethereum.
With fewer people providing liquidity, only those willing to take the risk of jail time and/or bagholding tokens they can't exchange continue to use the service, and that increases the risk of your particular account getting associated with a crime, and reduces the effectiveness with which the mixer can hide your identity.
I'm not aware of any mixing service on Hive but we do face essentially the same danger in the future. If a Hive account or service is blacklisted/sanctioned by the state, how many among us will defy the state and continue to accept Hive from blacklisted or sanctioned accounts, at risk of state violence? The US in particular is quite capable of extending its enforcement powers well past its borders.