On a purely technical note, something being "fully decentralized" would usually imply low reach. To amplify voices a platform has to be conceptually centralized

On a purely technical note, something being "fully decentralized" would usually imply low reach. To amplify voices a platform has to be conceptually centralized enough to allow for a common experience. Which comes with the ability to impose rules. People may disagree on what the rules should be, but the great majority do want some. The notion of huge swaths of people being sucked into some totally anonymous decentralized platform with no rules and nobody in charge sounds implausible.