In what can only be called a "double turns-out", Mastodon instances can be changed in ways to not be part of the federated group. So, I guess centralized might be the only way to have a unified communication channel. Within two days I've moved from one Mastodon instance to another. I've noticed that this is somewhat common.
Amanda, I agree, the social platform experiment has become tiring for me. My use of Facebook and Twitter have fallen off dramatically while my use of RSS feeds continues unabated. Even the act of POSSEing my content to social media is a chore. I have almost stopped doing it. And because of concerns about GDPR I no longer back feed comments and like from social silos. I disabled Brid.gy syndication to Facebook and Flickr and only occasionally syndicate to Twitter.
Avoiding syndication to social platforms has made discovery more challenging but I am hoping as the IndieWeb grows, this problem will be solved. We’ll find each other the old-fashioned “Web” way. For example, I discovered your post and your website via Chris Aldrich’s website.