I don't think it matters how democratically elected a centralized solution is, it will still require decisions to keep the platform profitable which disenfranchises the users that provide all the content for the platform.
Decentralizing reduces that overhead cost, removes the need for appealing to investors, and places the power back into the users hands. It's currently skewed because everyone is flocking to larger instances, but when people are finally comfortable with the platform we should see a load balancing. And, if people are worried about being defederated on their large instance, they can always self host for almost free and have access to everywhere.