Seattle metro area: Some of the right-of-ways have been converted into rail trails, so the map probably isn't THAT bad. But yeah the current state of US rail is depressing compared to what could have been (or yet could be!)

Theoretically rail trails can become rail lines once again but I am only really aware of one example where this kind of happened (the DC Purple Line)

Part of this is the rail trails only happen where there’s basically not even a ghost of a need for the tracks.

But trails alongside very inactive tracks is also becoming more common.