Offhand, I can’t think of any sf which has explained why a return of a feudal system is plausible
In the Vorkosigan series, the main events surround a planet with a feudal system. This is explained because the planet lost contact with the larger galactic civilization and regressed in tech level massively. Meanwhile certain powerful bandits and raiders became strong enough in the chaos and passed down their roles on to their children. Then when they ended up being reconnected with the advanced technology societies they became very quickly a feudal culture with advanced technology. One major aspects of the stories is how this is an inherently unstable situation. (I have to wonder if this is in deliberate contrast to something like Dune where society stagnates in a feudal system with advanced tech for hundreds of years.)
In the Vorkosigan series, the main events surround a planet with a feudal system. This is explained because the planet lost contact with the larger galactic civilization and regressed in tech level massively. Meanwhile certain powerful bandits and raiders became strong enough in the chaos and passed down their roles on to their children. Then when they ended up being reconnected with the advanced technology societies they became very quickly a feudal culture with advanced technology. One major aspects of the stories is how this is an inherently unstable situation. (I have to wonder if this is in deliberate contrast to something like Dune where society stagnates in a feudal system with advanced tech for hundreds of years.)