In my opinion, the core function of decentralization of the network is the security of the network. That no one entity, no groups can unilaterally gain control of the network and use it to their advantage. This security makes sure that integrity of the network, ownership of accounts/wallets are not broken.
This is achieved via DPOS consensus on Hive. Last I checked there is no large stakeholder or groups of stakeholders that have enough cumulative Hive Power that can perform such an attach on the network. If one to try to gain enough HP to gain control, the price of Hive go so high that they wouldn't be able to finish what they started.
This is what I mean with Hive is decentralized enough. In DPOS especially with a rewards distribution system of Hive, it should keep getting more and more decentralized over time.
I do not know what "bottom-up, multi-level, pure democrity consensus community governance system" is. But I can see many different systems can be built on top of Hive as a second layer. Just like different tribes have been experimenting with different systems.
If what you are suggesting is not within Delegated Proof of Stake (DPOS) system, I doubt it can be achieved as it would require changing the consensus mechanism altogether, which would mean creating a new blockchain.