federation is just one way to achieve some form of decentralization... but only on one axis. the axis of "service provider choice". what is needed alongside this is a great "unbundling" of services.
in the usa, if you want to sign up for just internet, companies often (more often in the past) force you to bundle in phone and tv service as well. we can think of one of fedi's current problems as the bundling of several services into a single provider -- identity, data, communication.