No friends share your thru-hiker vision? Walk it alone.
If it is a popular trail (PCT, AT, Colorado Trail, Spanish Camino) you will very likely meet people and establish friendships, possibly for life.
Even if you walk with a friend, or newfound friend, you should consider walking alone for some days.
It’s a different experience and will give you lots of time for introspection. You might also see more wildlife.
It is quite common for hiker friends to walk “alone together”: You maybe walk together for some hours of the day but many hours you are walking alone and then you meet up at a certain lunch-spot (i.e. at a creek) and plan to camp together for the night. This gives everybody a great opportunity to socialize and share the experiences while still following their own rhythm and enjoy some solitude: hiking speed, wake-up hour, pack-it-up time in the morning etc.