http://awuuwa.i2p/webpages/Fediverse%20vs%20Retroshare.html
Even if one of those big nodes gets taken down, it doesn't do any harm, no one's back catalogue of content is erased or followers lost. Just connect to a new middle node and resume operation as usual, as if nothing happened. Because it is the user who is sharing the content, not the node in the middle.