Spoilers... Marooned in Realtime has multiple groups of people travelling into the future, all having set out before a mysterious event that wiped out the rest

Spoilers... Marooned in Realtime has multiple groups of people travelling into the future, all having set out before a mysterious event that wiped out the rest oh humanity. They experience the evolution of the Earth, but the only human civilisation they experience is that of their fellow travelers. 'The Forever War' (referenced elsewhere here) in contrast has individuals who dip into evolving human civilisation, finding massive societal changes each time they return, so much so that 'home' becomes the time jumping army they belong to.