I seriously doubt their website failed because they used django and react, that's gotta be the most common tech stack of all time.
Rarely are UX issues there because of anything technical at all, just poor testing and poor polishing. Of course, things are way easier with a static site, since the back button Just Works(TM) in that case, but doesn't mean "overly dynamic sites" cannot have proper browser history.
To be honest, as a top host in my city, the only features that Couchsurfing was actually good for was discovery. Everything else was kinda broken or slow. It added to the charm, but it definitely wasn't much better than what you're claiming here for Couchers.