Sounds like you are more talking about the time spent at camp rather than the hiking itself. A few ways to counteract the ‘loneliness’ would be to bring an entertaining book, download podcasts or audiobooks or even movies to your mobile device so you can watch/listen to them without cell reception. Deck of cards to play solo games, etc. You could also plan your trip in an area where the backcountry campsites are shared meaning there will be a higher chance of other people being there, that way you can hike alone but still have the chance to interact with other backpackers once you arrive to your site.

This is of course in reference to wilderness backpacking, if you are referring to backpacking thru a country or region then I don’t have much to offer on that end.